AIM: To study the postoperative complications in patients with preoperative portal vein thrombosis (PVT) undergoing liver transplantation (LT) and to evaluate the complications with Doppler ultrasonography.METHOD...AIM: To study the postoperative complications in patients with preoperative portal vein thrombosis (PVT) undergoing liver transplantation (LT) and to evaluate the complications with Doppler ultrasonography.METHODS: Retrospective studies were performed on 284 patients undergoing LT (286 LT) with respect to pre- and postoperative clinical data and Doppler ultrasonography. According to the presence and grade of preoperative PVT, 286 LTs were divided into three groups: complete PVT (c-PVT), partial PVT (p-PVT) and non-PVT, with 22, 30 and 234 LTs, respectively. Analyses were carried out to compare the incidence of early postoperative complications.RESULTS: PVT, inferior vena cava (IVC) thrombosis, hepatic artery thrombosis (HAT) and biliary complications were found postoperatively. All complications were detected by routine Doppler ultrasonography and diagnoses made by ultrasound were confirmed by clinical data or/and other imaging studies. Nine out of 286 LTs had postoperative PVT. The incidence of the c-Pv-r group was 22.7%, which was higher than that of the p-Pv-r group (3.3%, P 〈 0.05) and non- PVT group (1.3%, P 〈 0.005). No difference was found between the p-PVT and non-PVT groups (P 〉 0.25). Of the 9 cases with postoperative PVT, recanalizations were achieved in 7 cases after anticoagulation under the guidance of ultrasound, 1 case received portal vein thrombectomy and 1 case died of acute injection. Ten LTs had postoperative 1VC thrombosis. The c-PVT group had a higher incidence of IVC thrombosis than the non- PVT group (9.1% vs 2.6%, P 〈 0.05); no significant difference was found between either the c-PV-T and p-PVT groups (9.1% vs 6.7%, P 〉 0.5) or between the p-PVT and non-PVT groups (P 〉 0.25). Nine cases with IVC thrombosis were cured by anticoagulation under the guidance of ultrasound, and 1 case gained natural cure without any medical treatment after 2 mo. HAT was found in 2 non-PVT cases, giving a rate of 0.7% among 286 LTs. Biliary complications were seen in 12 LTs. The incidence of biliary complications in the c-PVT, p-PVT and non-PVT groups was 9.1%, 3.3% and 4.3%, respectively (P 〉 0.25 for all), among which 2 stenosis led retransplantations and others were controlled by relative therapy.CONCLUSION: C-PVT patients tend to have a higher incidence of PVT and IVC thrombosis than non- PVT patients after LT. The incidence of postoperative complications in p-PVT patients does not differ from that of non-PVT patients, A relatively low incidence of HAT was seen in our study, Doppler ultrasonography is a convenient and efficient method for detecting posttransplant complications and plays an important role in guiding treatment.展开更多
We present the gray-scale ultrasonography (GSUS), power Doppler ultrasonography (PDUS), abdominal computed tomography (CT), and magnetic resonance imaging (MRI) findings for a case of splenic hamartoma in a 27...We present the gray-scale ultrasonography (GSUS), power Doppler ultrasonography (PDUS), abdominal computed tomography (CT), and magnetic resonance imaging (MRI) findings for a case of splenic hamartoma in a 27-year-old man, showing a φ 50 mm homogeneous, iso- and hypo-echoic splenic mass with evidence of a small plural cystic lesion. This splenic hamartoma showed increased vascularity on power Doppler sonograms. PDUS showed multiple circular blood flow signals inside the mass (i.e. a basket pattern), which was consistent with the small plural cystic lesion shown by GSUS. Spectral analysis also confirmed arterial and venous flow. CT scans showed that the mass had lowdensity relative to the normal spleen and MRI showed that the mass was isodense, relative to the normal spleen. Therefore, CT and MRI are not useful for the diagnosis of splenic hamartoma. Ultrasonography can be used to diagnose splenic hamartoma without administration of a contrast matedal and therefore is an indispensable method for the diagnosis of splenic hamartoma.展开更多
In seismic exploration for coal, seismic waves are very difficult to transmit downward because of high velocity protective layers, making the reflection information very hard to receive above ground. Based on the Snel...In seismic exploration for coal, seismic waves are very difficult to transmit downward because of high velocity protective layers, making the reflection information very hard to receive above ground. Based on the Snell law and the Zoeppritz equation, we studied the relationship between the incidence angle and reflection seismic wave energy using a forward model of level media. The result shows that the seismic wave energy has a sudden increase at the critical angle. Based on the energy propagation rule, using big offset to receive the seismic wave energy under a protective layer can effectively reduce its protection effect.展开更多
Concerning the PDRA (pulse doppler radar altimeter) designing and evaluation, owing to that the specifications of PDRA should be adaptively fixed according to the ETR (earth terrain return), and that in certain stages...Concerning the PDRA (pulse doppler radar altimeter) designing and evaluation, owing to that the specifications of PDRA should be adaptively fixed according to the ETR (earth terrain return), and that in certain stages of product evaluation of PDRA which means the designations of PDRA are successful or not, the usage of ETR are indispensable, so the terrain return from spherical earth is critically important. A complete analytic derivation of the antenna shot section model of PDRA and the bright section model constrained by pulse emitted from antenna are given. Furthermore, the doppler effect mode and the earth terrain RCF (radar crossing factor) model are constructively analyzed. Then, the computing methodology on PDRA, which are used to compute the scattering power, scattering doppler spectrum, and the scattering signal, is studied. Besides, in order to check the correctness and efficiency of the algorithm, computing examples of ETR (earth terrain return) under the supposing premises are furnished. Finally, the conclusion is drawn that the models and algorithm are rational, the computational precise is satisfactory, the cost of computing time is low.展开更多
The purpose of this study was to determine the efficacy of using an ultrasound contrast agent(levovist)to enhance the color Doppler imaging of liver neoplasms.Thirty patients with hepatic tu...The purpose of this study was to determine the efficacy of using an ultrasound contrast agent(levovist)to enhance the color Doppler imaging of liver neoplasms.Thirty patients with hepatic tumors were enrolled in this study.After intravenous administration of levovist,the color Doppler signals of normal hepatic vessels were enhanced.In various hepatic tumors,the different patterns of tumor vascularity were observed,which had not been demonstrated in conventional non contrast color Doppler imaging.In 11 of 16 patients with hepatocarcinoma,additional color Doppler signals were observed in the central part of the tumors.On the contrary,3 patients with metastatic liver lesions the enhanced color Doppler signals appear only at the peripheral of tumors.A typical rim like color enhancement was seen in 2 of the 3 cases.In six patients with hepatic hemangiomas contrast enhanced color Doppler imaging demonstrated the blood vessels at the margin of the neoplasms.Contrast enhanced color Doppler imaging improves the visualization of the hepatic neoplasm vascularity.This technique holds great promise for detecting small liver tumors and differentiating hepatic neoplasms.展开更多
An ensemble adjustment Kalman filter system is developed to assimilate Argo profiles into the Northwest Pacific MASNUM wave-circulation coupled model, which is based on the Princeton Ocean Model (POM). This model was ...An ensemble adjustment Kalman filter system is developed to assimilate Argo profiles into the Northwest Pacific MASNUM wave-circulation coupled model, which is based on the Princeton Ocean Model (POM). This model was recoded in FORTRAN-90 style, and some new data types were defined to improve the efficiency of system design and execution. This system is arranged for parallel computing by using UNIX shell scripts: it is easier with single models running separately with the required information exchanged through input/output files. Tests are carried out to check the performance of the system: one for checking the ensemble spread and another for the performance of assimilation of the Argo data in 2005. The first experiment shows that the assimilation system performs well. The comparison with the Satellite derived sea surface temperature (SST) shows that modeled SST errors are reduced after assimilation; at the same time, the spatial correlation between the simulated SST anomalies and the satellite data is improved because of Argo assimilation. Furthermore, the temporal evolution/trend of SST becomes much better than those results without data assimilation. The comparison against GTSPP profiles shows that the improvement is not only in the upper layers of ocean, but also in the deeper layers. All these results suggest that this system is potentially capable of reconstructing oceanic data sets that are of high quality and are temporally and spatially continuous.展开更多
The article is devoted to the psychoanalytic issues of the deconstruction of images of socialist ideals in Russian Sots Art--an ironic title of the artistic trend in which used a mixture signs of visual semiotics of ...The article is devoted to the psychoanalytic issues of the deconstruction of images of socialist ideals in Russian Sots Art--an ironic title of the artistic trend in which used a mixture signs of visual semiotics of "social realism" and "pop art" of the 1990-2000s. By comparing the idealization of the image of Lenin in Soviet art of the 1930-1950s with its grotesque interpretation in Sots Art works of the 1990s, it appears to be interesting to trace the functions of grotesque and caricature in the deconstruction of the canons of socialist realism. Thereupon, special interest is the role of the regression mechanism in the transformation of the ideals of socialist realism into laughable images.展开更多
Large amplitude internal solitary waves(ISWs) often exhibit highly nonlinear effects and may contribute significantly to mixing and energy transporting in the ocean.We observed highly nonlinear ISWs over the continent...Large amplitude internal solitary waves(ISWs) often exhibit highly nonlinear effects and may contribute significantly to mixing and energy transporting in the ocean.We observed highly nonlinear ISWs over the continental shelf of the northwestern South China Sea(19°35'N,112°E) in May 2005 during the Wenchang Internal Wave Experiment using in-situ time series data from an array of temperature and salinity sensors,and an acoustic Doppler current profiler(ADCP).We summarized the characteristics of the ISWs and compared them with those of existing internal wave theories.Particular attention has been paid to characterizing solitons in terms of the relationship between shape and amplitude-width.Comparison between theoretical prediction and observation results shows that the high nonlinearity of these waves is better represented by the second-order extended Korteweg-de Vries(KdV) theory than the first-order KdV model.These results indicate that the northwestern South China Sea(SCS) is rich in highly nonlinear ISWs that are an indispensable part of the energy budget of the internal waves in the northern South China Sea.展开更多
Empirical, formal, and speculative understandings of logic as identified by Hegel will be formalized. Being formalized the propositions will be deduced from how probabilities can be used to make decisions by appropria...Empirical, formal, and speculative understandings of logic as identified by Hegel will be formalized. Being formalized the propositions will be deduced from how probabilities can be used to make decisions by appropriating Hegel's concept of being two-sided for inferences. This will work for what I will call grounded as opposed to ungrounded probability functions. The domain of their values will be decided by a three-valued modal relation of the binomial probability function. Keynes (1920, Ch. IV ~17) and Popper's (1959, Ch. 59) solution to the problem of unknown proportions will be challenged by an understanding of logic that puts the content of what the axioms mean for making rational decisions before their mere being. What is true for the different types inferences will then work for the principle of the dialectic in contrast to the two proposed by Hume and the one proposed by David Lewis. In this way, it will be demonstrated that Hegel's understanding of logic is still more advanced than one that fails to recognize it falls within the scope of the dialectic. Dialectic as such will be a principle where the different understandings of a predicated logic will have a modal value within a higher standpoint of system.展开更多
AIM: To assess the role of echo-Doppler ultrasonography in postprandial hyperemia in cirrhotic patients by comparing the results with the hepatic vein catheterization technique.METHODS: Patients with cirrhosis, admitt...AIM: To assess the role of echo-Doppler ultrasonography in postprandial hyperemia in cirrhotic patients by comparing the results with the hepatic vein catheterization technique.METHODS: Patients with cirrhosis, admitted to the portal hemodynamic laboratory were included into the study. After an overnight fast, echo-Doppler ultrasonography (basal and 30 min after a standard meal) and hemodynamic studies by hepatic vein catheterization (basal, 15 min and 30 min after a standard meal) were performed. Ensure Plus (Abbot Laboratories, North Chicago, IL) was used as the standard liquid meal. Correlation analysis of the echo-Doppler and hepatic vein catheterization measurements were done for the basal and postprandial periods.RESULTS: Eleven patients with cirrhosis (5 Child A, 4 Child B, 2 Child C) were enrolled into the study. After the standard meal, 8 of the 11 patients showed postprandial hyperemia with increase in portal blood flow, portal blood velocity and hepatic venous pressure gradient. Hepatic venous pressure gradient in the postprandial period correlated positively with postprandial portal blood velocity (r = 0.8, P < 0.05) and correlated inversely with postprandial superior mesenteric artery pulsatility index (r = -1, P < 0.01).CONCLUSION: Postprandial hyperemia can be efficiently measured by echo-Doppler ultrasonography and the results are comparable to those obtained with the hemodynamic studies.展开更多
This paper reviews and adds to previous arguments for the thesis that Karl Popper was mistaken to have rejected hypothetico-deductive confirmation. By turning from the positive idea of verification to the negative ide...This paper reviews and adds to previous arguments for the thesis that Karl Popper was mistaken to have rejected hypothetico-deductive confirmation. By turning from the positive idea of verification to the negative idea of criticism, Popper believed that he had turned his back on induction. He believed he had "solved" the "problem of induction" by providing a non-inductive account of corroboration. Popper used the term "corroboration" rather than confirmation which he believed was too closely allied to the notion of the inductive or probabilistic support that a theory can receive from evidence. Wesley Salmon's (1967) "concept of confirming evidence" and Clark Glymour's (1980) "bootstrap conception of evidence for theory" both defended respectively the thesis that passed tests can be confirmed by evidence or warranted by the degree of probability. Using a sequence of symbols in logical form or analysis, I shall further defend the concept to hypothetico-deductive confirmation in order to show that the known weaknesses of Popper's critical rationalism are remediable, once the notion of evidence for theories is brought back into consideration.展开更多
There is no patina of doubt that the central philosophical theories of Karl Popper and Thomas Kuhn concerning the nature, substance and method for acquiring scientific knowledge constitute milestones in 20th century p...There is no patina of doubt that the central philosophical theories of Karl Popper and Thomas Kuhn concerning the nature, substance and method for acquiring scientific knowledge constitute milestones in 20th century philosophy of science. Just as Popper's fundamental work on the subject, The Logic of Scientific Discovery, marked a decisive break with inductivist epistemologies, Kuhn's magnum opus, The Structure of Scientific Revolutions (1962, enlarged ed. 1970), inaugurated the coming of age of the historical turn in the philosophy of science. Some scholars seem to consider the main doctrines of both philosophers as irreconcilables or contradictories. This explains why, for example Popper and Popperians such as Imre Lakatos and John Watkins describe themselves as "critical rationalists", whereas they refer to Kuhn as an "irrationalist" or "relativist"-appellations that the latter has consistently rejected. The debate between Popper and Kuhn, especially as contained in an important work, Criticism and the Growth of Knowledge (1970), highlights some of the knotty problems connected with philosophical appraisals of science. It also demonstrates the strengths and weaknesses of logistic approaches in the philosophy of science, on the one hand, and of historically informed socio-psychological analysis of science, on the other. In this paper, we reexamine the Popper-Kuhn controversy from an experimentalist perspective. In other words, we argue that the ideas of testing and normal science can be systematically accommodated by fine-structure dissection of empirical research through which scientists learn about the world, based on the assumption that the progress of science is the growth of experimental knowledge-a fact often neglected in theory-dominated philosophies of science. Taking discovery of the cosmic background radiation by Arno Penzias and Robert Wilson as example, the paper argues that important scientific discoveries have been accomplished even in the absence of theory in any obvious sense, a situation that conflicts with the theory-dominated models of Popper and Kuhn. Thus, it offers an account of how practicing scientists learn from research to control errors and avoid blind alleys. The paper affirms, in conclusion, that going beyond the theories of Popper and Kuhn requires that philosophers of science should take what scientists learn from experiments seriously when theorising about science, by taking into account normal testing or error detection and control strategies through which scientific knowledge is acquired and extended展开更多
The South China Sea(SCS) is one of the most active areas of internal waves.We undertook a program of physical oceanography in the northern South China Sea from June to July of 2009,and conducted a 1-day observation fr...The South China Sea(SCS) is one of the most active areas of internal waves.We undertook a program of physical oceanography in the northern South China Sea from June to July of 2009,and conducted a 1-day observation from 15:40 of June 24 to 16:40 of June 25 using a chain of instruments,including temperature sensors,pressure sensors and temperature-pressure meters at a site(117.5°E,21°N) northeast of the Dongsha Islands.We measured fluctuating tidal and subtidal properties with the thermistor-chain and a ship-mounted Acoustic Doppler Current Profiler,and observed a large-amplitude nonlinear internal wave passing the site followed by a number of small ones.To further investigate this phenomenon,we collected the tidal constituents from the TPXO7.1 dataset to evaluate the tidal characteristics at and around the recording site,from which we knew that the amplitude of the nonlinear internal wave was about 120 m and the period about 20 min.The horizontal and vertical velocities induced by the soliton were approximately 2 m/s and 0.5 m/s,respectively.This soliton occurred 2-3 days after a spring tide.展开更多
In this article, we study the Lax pairs of -dimensional equation: the modified generalized dispersive long wave (MGDLW) equation. Based on the well-known binary Darboux transformation, we dig out the recursion formula...In this article, we study the Lax pairs of -dimensional equation: the modified generalized dispersive long wave (MGDLW) equation. Based on the well-known binary Darboux transformation, we dig out the recursion formulas of the first part of the Lax pairs. Then by further discussion and doing some revisional work, we make the recursion formulas fit for the second part of Lax pairs. At last, some solutions to the MGDLW equation are worked out by using the recursion formula.展开更多
Electron cyclotron resonance heating (ECRH) is one of the main auxiliary heating schemes for the HL-2A tokamak. Routinely, the ohmic heating can provide a heating power about 300-450 kW in this device ( estimated f...Electron cyclotron resonance heating (ECRH) is one of the main auxiliary heating schemes for the HL-2A tokamak. Routinely, the ohmic heating can provide a heating power about 300-450 kW in this device ( estimated from that the total toroidal current is about 300 kA while the totoidal voltage is 1-1.5 V). The total power for the ECRH now is 1 MW and in future 2 MW.展开更多
文摘AIM: To study the postoperative complications in patients with preoperative portal vein thrombosis (PVT) undergoing liver transplantation (LT) and to evaluate the complications with Doppler ultrasonography.METHODS: Retrospective studies were performed on 284 patients undergoing LT (286 LT) with respect to pre- and postoperative clinical data and Doppler ultrasonography. According to the presence and grade of preoperative PVT, 286 LTs were divided into three groups: complete PVT (c-PVT), partial PVT (p-PVT) and non-PVT, with 22, 30 and 234 LTs, respectively. Analyses were carried out to compare the incidence of early postoperative complications.RESULTS: PVT, inferior vena cava (IVC) thrombosis, hepatic artery thrombosis (HAT) and biliary complications were found postoperatively. All complications were detected by routine Doppler ultrasonography and diagnoses made by ultrasound were confirmed by clinical data or/and other imaging studies. Nine out of 286 LTs had postoperative PVT. The incidence of the c-Pv-r group was 22.7%, which was higher than that of the p-Pv-r group (3.3%, P 〈 0.05) and non- PVT group (1.3%, P 〈 0.005). No difference was found between the p-PVT and non-PVT groups (P 〉 0.25). Of the 9 cases with postoperative PVT, recanalizations were achieved in 7 cases after anticoagulation under the guidance of ultrasound, 1 case received portal vein thrombectomy and 1 case died of acute injection. Ten LTs had postoperative 1VC thrombosis. The c-PVT group had a higher incidence of IVC thrombosis than the non- PVT group (9.1% vs 2.6%, P 〈 0.05); no significant difference was found between either the c-PV-T and p-PVT groups (9.1% vs 6.7%, P 〉 0.5) or between the p-PVT and non-PVT groups (P 〉 0.25). Nine cases with IVC thrombosis were cured by anticoagulation under the guidance of ultrasound, and 1 case gained natural cure without any medical treatment after 2 mo. HAT was found in 2 non-PVT cases, giving a rate of 0.7% among 286 LTs. Biliary complications were seen in 12 LTs. The incidence of biliary complications in the c-PVT, p-PVT and non-PVT groups was 9.1%, 3.3% and 4.3%, respectively (P 〉 0.25 for all), among which 2 stenosis led retransplantations and others were controlled by relative therapy.CONCLUSION: C-PVT patients tend to have a higher incidence of PVT and IVC thrombosis than non- PVT patients after LT. The incidence of postoperative complications in p-PVT patients does not differ from that of non-PVT patients, A relatively low incidence of HAT was seen in our study, Doppler ultrasonography is a convenient and efficient method for detecting posttransplant complications and plays an important role in guiding treatment.
文摘We present the gray-scale ultrasonography (GSUS), power Doppler ultrasonography (PDUS), abdominal computed tomography (CT), and magnetic resonance imaging (MRI) findings for a case of splenic hamartoma in a 27-year-old man, showing a φ 50 mm homogeneous, iso- and hypo-echoic splenic mass with evidence of a small plural cystic lesion. This splenic hamartoma showed increased vascularity on power Doppler sonograms. PDUS showed multiple circular blood flow signals inside the mass (i.e. a basket pattern), which was consistent with the small plural cystic lesion shown by GSUS. Spectral analysis also confirmed arterial and venous flow. CT scans showed that the mass had lowdensity relative to the normal spleen and MRI showed that the mass was isodense, relative to the normal spleen. Therefore, CT and MRI are not useful for the diagnosis of splenic hamartoma. Ultrasonography can be used to diagnose splenic hamartoma without administration of a contrast matedal and therefore is an indispensable method for the diagnosis of splenic hamartoma.
基金Projects 40574058 supported by the National Natural Science Foundation of China2005cb221500 by the National Basic Research Program of China 03(2007) by the Scientific and Technological Project about Geology and Mineral Resources of Henan Land Resources Department
文摘In seismic exploration for coal, seismic waves are very difficult to transmit downward because of high velocity protective layers, making the reflection information very hard to receive above ground. Based on the Snell law and the Zoeppritz equation, we studied the relationship between the incidence angle and reflection seismic wave energy using a forward model of level media. The result shows that the seismic wave energy has a sudden increase at the critical angle. Based on the energy propagation rule, using big offset to receive the seismic wave energy under a protective layer can effectively reduce its protection effect.
文摘Concerning the PDRA (pulse doppler radar altimeter) designing and evaluation, owing to that the specifications of PDRA should be adaptively fixed according to the ETR (earth terrain return), and that in certain stages of product evaluation of PDRA which means the designations of PDRA are successful or not, the usage of ETR are indispensable, so the terrain return from spherical earth is critically important. A complete analytic derivation of the antenna shot section model of PDRA and the bright section model constrained by pulse emitted from antenna are given. Furthermore, the doppler effect mode and the earth terrain RCF (radar crossing factor) model are constructively analyzed. Then, the computing methodology on PDRA, which are used to compute the scattering power, scattering doppler spectrum, and the scattering signal, is studied. Besides, in order to check the correctness and efficiency of the algorithm, computing examples of ETR (earth terrain return) under the supposing premises are furnished. Finally, the conclusion is drawn that the models and algorithm are rational, the computational precise is satisfactory, the cost of computing time is low.
文摘The purpose of this study was to determine the efficacy of using an ultrasound contrast agent(levovist)to enhance the color Doppler imaging of liver neoplasms.Thirty patients with hepatic tumors were enrolled in this study.After intravenous administration of levovist,the color Doppler signals of normal hepatic vessels were enhanced.In various hepatic tumors,the different patterns of tumor vascularity were observed,which had not been demonstrated in conventional non contrast color Doppler imaging.In 11 of 16 patients with hepatocarcinoma,additional color Doppler signals were observed in the central part of the tumors.On the contrary,3 patients with metastatic liver lesions the enhanced color Doppler signals appear only at the peripheral of tumors.A typical rim like color enhancement was seen in 2 of the 3 cases.In six patients with hepatic hemangiomas contrast enhanced color Doppler imaging demonstrated the blood vessels at the margin of the neoplasms.Contrast enhanced color Doppler imaging improves the visualization of the hepatic neoplasm vascularity.This technique holds great promise for detecting small liver tumors and differentiating hepatic neoplasms.
基金Supported by the Project of National Basic Research Program of China (No. 2007CB816002)Special Fund for Fundamental Scientific Research (No. 2008G08)
文摘An ensemble adjustment Kalman filter system is developed to assimilate Argo profiles into the Northwest Pacific MASNUM wave-circulation coupled model, which is based on the Princeton Ocean Model (POM). This model was recoded in FORTRAN-90 style, and some new data types were defined to improve the efficiency of system design and execution. This system is arranged for parallel computing by using UNIX shell scripts: it is easier with single models running separately with the required information exchanged through input/output files. Tests are carried out to check the performance of the system: one for checking the ensemble spread and another for the performance of assimilation of the Argo data in 2005. The first experiment shows that the assimilation system performs well. The comparison with the Satellite derived sea surface temperature (SST) shows that modeled SST errors are reduced after assimilation; at the same time, the spatial correlation between the simulated SST anomalies and the satellite data is improved because of Argo assimilation. Furthermore, the temporal evolution/trend of SST becomes much better than those results without data assimilation. The comparison against GTSPP profiles shows that the improvement is not only in the upper layers of ocean, but also in the deeper layers. All these results suggest that this system is potentially capable of reconstructing oceanic data sets that are of high quality and are temporally and spatially continuous.
文摘The article is devoted to the psychoanalytic issues of the deconstruction of images of socialist ideals in Russian Sots Art--an ironic title of the artistic trend in which used a mixture signs of visual semiotics of "social realism" and "pop art" of the 1990-2000s. By comparing the idealization of the image of Lenin in Soviet art of the 1930-1950s with its grotesque interpretation in Sots Art works of the 1990s, it appears to be interesting to trace the functions of grotesque and caricature in the deconstruction of the canons of socialist realism. Thereupon, special interest is the role of the regression mechanism in the transformation of the ideals of socialist realism into laughable images.
基金Supported by the Knowledge Innovation Program of Chinese Academy of Sciences (No.KZCX1-YW-12)the National High Technology Research and Development Program of China (863 program) (No.2008AA09A401,No.2006AA09A109)
文摘Large amplitude internal solitary waves(ISWs) often exhibit highly nonlinear effects and may contribute significantly to mixing and energy transporting in the ocean.We observed highly nonlinear ISWs over the continental shelf of the northwestern South China Sea(19°35'N,112°E) in May 2005 during the Wenchang Internal Wave Experiment using in-situ time series data from an array of temperature and salinity sensors,and an acoustic Doppler current profiler(ADCP).We summarized the characteristics of the ISWs and compared them with those of existing internal wave theories.Particular attention has been paid to characterizing solitons in terms of the relationship between shape and amplitude-width.Comparison between theoretical prediction and observation results shows that the high nonlinearity of these waves is better represented by the second-order extended Korteweg-de Vries(KdV) theory than the first-order KdV model.These results indicate that the northwestern South China Sea(SCS) is rich in highly nonlinear ISWs that are an indispensable part of the energy budget of the internal waves in the northern South China Sea.
文摘Empirical, formal, and speculative understandings of logic as identified by Hegel will be formalized. Being formalized the propositions will be deduced from how probabilities can be used to make decisions by appropriating Hegel's concept of being two-sided for inferences. This will work for what I will call grounded as opposed to ungrounded probability functions. The domain of their values will be decided by a three-valued modal relation of the binomial probability function. Keynes (1920, Ch. IV ~17) and Popper's (1959, Ch. 59) solution to the problem of unknown proportions will be challenged by an understanding of logic that puts the content of what the axioms mean for making rational decisions before their mere being. What is true for the different types inferences will then work for the principle of the dialectic in contrast to the two proposed by Hume and the one proposed by David Lewis. In this way, it will be demonstrated that Hegel's understanding of logic is still more advanced than one that fails to recognize it falls within the scope of the dialectic. Dialectic as such will be a principle where the different understandings of a predicated logic will have a modal value within a higher standpoint of system.
文摘AIM: To assess the role of echo-Doppler ultrasonography in postprandial hyperemia in cirrhotic patients by comparing the results with the hepatic vein catheterization technique.METHODS: Patients with cirrhosis, admitted to the portal hemodynamic laboratory were included into the study. After an overnight fast, echo-Doppler ultrasonography (basal and 30 min after a standard meal) and hemodynamic studies by hepatic vein catheterization (basal, 15 min and 30 min after a standard meal) were performed. Ensure Plus (Abbot Laboratories, North Chicago, IL) was used as the standard liquid meal. Correlation analysis of the echo-Doppler and hepatic vein catheterization measurements were done for the basal and postprandial periods.RESULTS: Eleven patients with cirrhosis (5 Child A, 4 Child B, 2 Child C) were enrolled into the study. After the standard meal, 8 of the 11 patients showed postprandial hyperemia with increase in portal blood flow, portal blood velocity and hepatic venous pressure gradient. Hepatic venous pressure gradient in the postprandial period correlated positively with postprandial portal blood velocity (r = 0.8, P < 0.05) and correlated inversely with postprandial superior mesenteric artery pulsatility index (r = -1, P < 0.01).CONCLUSION: Postprandial hyperemia can be efficiently measured by echo-Doppler ultrasonography and the results are comparable to those obtained with the hemodynamic studies.
文摘This paper reviews and adds to previous arguments for the thesis that Karl Popper was mistaken to have rejected hypothetico-deductive confirmation. By turning from the positive idea of verification to the negative idea of criticism, Popper believed that he had turned his back on induction. He believed he had "solved" the "problem of induction" by providing a non-inductive account of corroboration. Popper used the term "corroboration" rather than confirmation which he believed was too closely allied to the notion of the inductive or probabilistic support that a theory can receive from evidence. Wesley Salmon's (1967) "concept of confirming evidence" and Clark Glymour's (1980) "bootstrap conception of evidence for theory" both defended respectively the thesis that passed tests can be confirmed by evidence or warranted by the degree of probability. Using a sequence of symbols in logical form or analysis, I shall further defend the concept to hypothetico-deductive confirmation in order to show that the known weaknesses of Popper's critical rationalism are remediable, once the notion of evidence for theories is brought back into consideration.
文摘There is no patina of doubt that the central philosophical theories of Karl Popper and Thomas Kuhn concerning the nature, substance and method for acquiring scientific knowledge constitute milestones in 20th century philosophy of science. Just as Popper's fundamental work on the subject, The Logic of Scientific Discovery, marked a decisive break with inductivist epistemologies, Kuhn's magnum opus, The Structure of Scientific Revolutions (1962, enlarged ed. 1970), inaugurated the coming of age of the historical turn in the philosophy of science. Some scholars seem to consider the main doctrines of both philosophers as irreconcilables or contradictories. This explains why, for example Popper and Popperians such as Imre Lakatos and John Watkins describe themselves as "critical rationalists", whereas they refer to Kuhn as an "irrationalist" or "relativist"-appellations that the latter has consistently rejected. The debate between Popper and Kuhn, especially as contained in an important work, Criticism and the Growth of Knowledge (1970), highlights some of the knotty problems connected with philosophical appraisals of science. It also demonstrates the strengths and weaknesses of logistic approaches in the philosophy of science, on the one hand, and of historically informed socio-psychological analysis of science, on the other. In this paper, we reexamine the Popper-Kuhn controversy from an experimentalist perspective. In other words, we argue that the ideas of testing and normal science can be systematically accommodated by fine-structure dissection of empirical research through which scientists learn about the world, based on the assumption that the progress of science is the growth of experimental knowledge-a fact often neglected in theory-dominated philosophies of science. Taking discovery of the cosmic background radiation by Arno Penzias and Robert Wilson as example, the paper argues that important scientific discoveries have been accomplished even in the absence of theory in any obvious sense, a situation that conflicts with the theory-dominated models of Popper and Kuhn. Thus, it offers an account of how practicing scientists learn from research to control errors and avoid blind alleys. The paper affirms, in conclusion, that going beyond the theories of Popper and Kuhn requires that philosophers of science should take what scientists learn from experiments seriously when theorising about science, by taking into account normal testing or error detection and control strategies through which scientific knowledge is acquired and extended
基金Supported by the Knowledge Innovation Program of Chinese Academy of Sciences (Nos.KZCX1-YW-12,KZCX2-YW-201)the National High Technology Research and Development Program of China (863 Program) (No.2008AA09A402)
文摘The South China Sea(SCS) is one of the most active areas of internal waves.We undertook a program of physical oceanography in the northern South China Sea from June to July of 2009,and conducted a 1-day observation from 15:40 of June 24 to 16:40 of June 25 using a chain of instruments,including temperature sensors,pressure sensors and temperature-pressure meters at a site(117.5°E,21°N) northeast of the Dongsha Islands.We measured fluctuating tidal and subtidal properties with the thermistor-chain and a ship-mounted Acoustic Doppler Current Profiler,and observed a large-amplitude nonlinear internal wave passing the site followed by a number of small ones.To further investigate this phenomenon,we collected the tidal constituents from the TPXO7.1 dataset to evaluate the tidal characteristics at and around the recording site,from which we knew that the amplitude of the nonlinear internal wave was about 120 m and the period about 20 min.The horizontal and vertical velocities induced by the soliton were approximately 2 m/s and 0.5 m/s,respectively.This soliton occurred 2-3 days after a spring tide.
基金The project supported by National Natural Science Foundation of China under Grant No.10101025
文摘In this article, we study the Lax pairs of -dimensional equation: the modified generalized dispersive long wave (MGDLW) equation. Based on the well-known binary Darboux transformation, we dig out the recursion formulas of the first part of the Lax pairs. Then by further discussion and doing some revisional work, we make the recursion formulas fit for the second part of Lax pairs. At last, some solutions to the MGDLW equation are worked out by using the recursion formula.
文摘Electron cyclotron resonance heating (ECRH) is one of the main auxiliary heating schemes for the HL-2A tokamak. Routinely, the ohmic heating can provide a heating power about 300-450 kW in this device ( estimated from that the total toroidal current is about 300 kA while the totoidal voltage is 1-1.5 V). The total power for the ECRH now is 1 MW and in future 2 MW.