Objective: To investigate the uptake rate of prostate specific antigen(PSA) testing among Hong Kong Chinese males aged 50 or above, and identify factors associated with the likelihood of undergoing a PSA test.Methods:...Objective: To investigate the uptake rate of prostate specific antigen(PSA) testing among Hong Kong Chinese males aged 50 or above, and identify factors associated with the likelihood of undergoing a PSA test.Methods: A population-based telephone survey was conducted in Hong Kong in 2007. The survey covered demographic information, perceived health status, use of complementary therapy, cancer screening behavior, perceived susceptibility to cancer and family history of cancer. Descriptive statistics, percentages and logistic regression analysis were used for data analysis.Results: A total of 1,002 men aged 50 or above took part in the study(response rate =67%), and the uptake rate of PSA testing was found to be 10%. Employment status, use of complementary therapy, perceiving regular visits to a doctor as good for health and the recommendations of health professionals were significant factors associated with PSA testing.Conclusion: The uptake rate of PSA testing in the study population was very low. Among all the factors identified, recommendations from health professionals had the strongest association with the uptake of PSA testing, and they should therefore take an active role in educating this population about cancer prevention and detection.展开更多
Inundation of the Three Gorges Reservoir has created a 30-m water-level fluctuation zone with seasonal hydrological alternations of submergence and exposure, which may greatly affect soil properties and bank stability...Inundation of the Three Gorges Reservoir has created a 30-m water-level fluctuation zone with seasonal hydrological alternations of submergence and exposure, which may greatly affect soil properties and bank stability. The aim of this study was to investigate the response of soil pore structure to seasonal water-level fluctuation in the reservoir, and particularly, the hydrological change of wetting and drying cycles. Soil pore structure was visualized with industrial X-ray computed tomography and digital image analysis techniques. The results showed that soil total porosity(? 100 ?m), total pore number, total throat number, and mean throat surface area increased significantly under wetting and drying cycles. Soil porosity, pore number and throat numberwithin each size class increased in the course of wetting and drying cycles. The coordination number, degree of anisotropy and fractal dimension were indicating an increase. In contrast, the mean shape factor, pore-throat ratio, and Euler-Poincaré number decreased due to wetting and drying cycles. These illustrated that the wetting and drying cycles made soil pore structure become more porous, continuous, heterogeneous and complex. It can thus be deduced that the water-level fluctuation would modify soil porosity, pore size distribution, and pore morphology in the Three Gorges Reservoir, which may have profound implications for soil processes, soil functions, and bank stability.展开更多
Neutron radiography is one of radiography non-destructive testing.It is a valuable complementary of X and γ rays radiography.The present status and history of neutron radiography in China was described briefly,facili...Neutron radiography is one of radiography non-destructive testing.It is a valuable complementary of X and γ rays radiography.The present status and history of neutron radiography in China was described briefly,facilities of neutron radiography and their development were introduced in this paper.展开更多
My camera lens is so illusionary that the authenticity of the Forbidden City is fading away. And my perspective is as narrow as an awl which slowly stings into the profundity of history... —Li
Since the beginning of human civilization, the existence of a variety of production and life, etiquette and other social customs are obvious. The invention of photography is natural firstly used to the performance of ...Since the beginning of human civilization, the existence of a variety of production and life, etiquette and other social customs are obvious. The invention of photography is natural firstly used to the performance of various phenomena of human existence. Not until 1993 did Folk photography was formally proposed and was quickly accepted by the public. Folk photographer should have a certain amount of theoretical knowledge of folklore, ethnology, anthropology, and folklore should familiar with the laws of photography. Folk photographer should not only be able to skillfully use a variety of photographic techniques to create photographer, but also have the ability of folklore studies, which means a certain level of theory and master certain research methods. Folk photography creative process is a cultural experience and explores the process of discovery. Folk photography is methods and means to record, release and heritage attending profound traditional Chinese culture. Folk photography through a unique form of expression, with its visual image, embodies the academic value of folk history, the development of human history, cultural heritage and makes a positive contribution to the spread. In the 21st century, China' s social stable, economic development rapidly, which provide a good folk photography authoring environment. Folk photography range will also change with the development of folk and continuously expanding, concerns and reflections about the new folk themes have yet to be excavated, to meet the needs of social development.展开更多
We picked new traveltime residual datasets in three frequency bands (0.02%). 1,0.1-0.8, and 0.8-2.0 Hz) for P-waves from 793 teleseismic events and two frequency bands (0.02-0.1 and 0.1-0.8 Hz) for S-waves from 3...We picked new traveltime residual datasets in three frequency bands (0.02%). 1,0.1-0.8, and 0.8-2.0 Hz) for P-waves from 793 teleseismic events and two frequency bands (0.02-0.1 and 0.1-0.8 Hz) for S-waves from 310 teleseismic events, recorded by 389 permanent stations of the China National Seismic Network and 832 broadband stations of 10 temporary arrays deployed in the North China Craton (NCC) region. The final datasets are composed of 65628 P-arrivals and 47050 S-arrivals. Based on previous research and our team's 2012 tomographic work, we constructed new three-dimensional P-velocity and S- velocity models of the NCC through some improvements, such as augmenting a much denser station coverage in the western NCC, considering the incident angle effect in crustal correction and using a multi-frequency joint inversion tomographic technique. The new velocity models provide several salient features, from which we draw possible inferences on regional dynamic processes. We observed high-velocity anomalies in the mantle transition zone (MTZ). Obvious morphological het- erogeneities suggest buckling and/or fragmentation of the subducted Pacific slab, and some of the slab materials are visible below 660-kin discontinuities. The velocity structure of the eastern NCC is dominated by small-scale lateral heterogeneities. At shallow depths, high-velocity anomalies beneath the southern part of the eastern NCC and the Yanshan region likely represent a remnant of cratonic lithosphere, which may suggest that the NCC destruction is spatially non-uniform. We also detected a high-velocity anomaly in the Sulu Orogen extending downward to -300 kin, which is seemingly controlled by the Tan-Lu Fault. The northern boundary of this anomaly spatially coincides with the Yantai-Qingdao-Wulian Fault, and is likely a remnant of the Yangtze cratonic lithosphere subducting northwestward. Significant low-velocity anomalies imaged beneath the central NCC show a spatial discordance between their northern and southern parts. The northern low-velocity anomaly extends downward to the top of MTZ with a lateral NW-SE strike, whereas the southern one tapers off at -200-300 kin. Low-velocity anomalies are present beneath the Phanerozoic orogenic belts surrounding the NCC, the Paleoproterozoic Trans-North China Orogen, and the Tan-Lu Fault. This feature not only shows excellent spatial correlation with the orogens at the surface, it also exhibits a consistent vertical continuity in a depth range of 60-250 km. This intriguing feature suggests that the collisional orogenic belts and Tan-Lu Fault are inherited weak zones, which may play a key role in craton destruction. By combining multidisciplinary results in this area, we suggest that the spatial heterogeneities associated with the NCC destruction most likely result from the combined effects of a spatially non-uniform distribution of wet upwellings triggered by the subducted Pacific slab and pre-existing weak zones in the eratonic lithosphere.展开更多
39473 Pn travel times are inverted to tomographically image both lateral variation and anisotropy of uppermost mantle velocities beneath China continent. The result indicates that the overall average Pn velocity of up...39473 Pn travel times are inverted to tomographically image both lateral variation and anisotropy of uppermost mantle velocities beneath China continent. The result indicates that the overall average Pn velocity of uppermost mantle in the studied region is 8.0 km/s and the regional velocity fluctuation varies from ?0.30 km/s to +0.35 km/s. Pn velocities higher than 8.2 km/s are found in the regions surrounding Qingzang Plateau, such as Junggar Basin, Tarim Basin, Qaidam Basin and Sichun Basin. Pn velocities slightly lower than the average are found in western Sichuan and Yunnan, Shanxi Graben and Bohai Bay region. A Pn velocity as low as 7.8 km/s may exist in the region striding the boundary between Guangxi and Guangdong provinces. In general, Pn velocity in tectonically stable region like cratonic platform tends to be high, while that in tectonically active region tends to be low. The regions in compressive setting usually show higher Pn velocity, while extensional basins or grabens generally display lower one. Anisotropy of Pn velocity is seen in some regions. In the southeastern region of Qingzang Plateau the directions of fastest Pn velocity show a rotation pattern, which may be related to southeastward escape of the plateau material due to the collision and compression of Indian Plate to Asia along Himalaya arc. Notable anisotropy also exists around Bohai Bay region, likely indicating crustal extending and possible magma activity therein.展开更多
Three-dimensional velocity images of the crust and upper mantlebeneath orogenic belts and adjacent basins of the northwestern continent of China are reconstructed by seismic tomography, based on arrival data of P wave...Three-dimensional velocity images of the crust and upper mantlebeneath orogenic belts and adjacent basins of the northwestern continent of China are reconstructed by seismic tomography, based on arrival data of P wave recorded in seismic networks in Xinjiang, Qinghai, Gansu of China and Kyrgyzstan. The velocity images of upper crust demonstrate the tectonic framework on the ground surface. High velocities are observed beneath orogenic belts, and low velocities are observed in the basins and depressions that are obviously related to unconsolidated sediments. The velocity image in mid-crust maintains the above features, and in addition low velocities appear in some earthquake regions and a low velocity boundary separates the western Tianshan Mts. from eastern Tianshan Mts. The orogenic belts and the northern Tibetan plateau have a Moho depth over 50 km, whereas the depths of the Moho in basins and depressions are smaller than 50 km. The velocity images of upper mantle clearly reveal the colliding relationship and location of deep boundaries of the continental blocks in northwestern China, indicating a weakness of the upper mantle structure of orogenic belts. The top depth of upper mantle asthenosphere varies from place to place. It seems shallower under the northern Tibetan plateau, Altay and Qilian Mts., and deeper under the Tarim and Tianshan regions. Hot mantle probably rose to the bottom of some orogenic belts along tectonic boundaries when continental blocks collided to each other. Therefore their dynamic features are closely correlated to the formation and evolution of orogenic belts in northwestern China.展开更多
基金supported by the Chinese University of Hong Kong
文摘Objective: To investigate the uptake rate of prostate specific antigen(PSA) testing among Hong Kong Chinese males aged 50 or above, and identify factors associated with the likelihood of undergoing a PSA test.Methods: A population-based telephone survey was conducted in Hong Kong in 2007. The survey covered demographic information, perceived health status, use of complementary therapy, cancer screening behavior, perceived susceptibility to cancer and family history of cancer. Descriptive statistics, percentages and logistic regression analysis were used for data analysis.Results: A total of 1,002 men aged 50 or above took part in the study(response rate =67%), and the uptake rate of PSA testing was found to be 10%. Employment status, use of complementary therapy, perceiving regular visits to a doctor as good for health and the recommendations of health professionals were significant factors associated with PSA testing.Conclusion: The uptake rate of PSA testing in the study population was very low. Among all the factors identified, recommendations from health professionals had the strongest association with the uptake of PSA testing, and they should therefore take an active role in educating this population about cancer prevention and detection.
基金funded by the National Natural Science Foundation of China(Grant No.41771321,41771320 and 41571278)Sichuan Science and Technology Program(Grant No.2018SZ0132)
文摘Inundation of the Three Gorges Reservoir has created a 30-m water-level fluctuation zone with seasonal hydrological alternations of submergence and exposure, which may greatly affect soil properties and bank stability. The aim of this study was to investigate the response of soil pore structure to seasonal water-level fluctuation in the reservoir, and particularly, the hydrological change of wetting and drying cycles. Soil pore structure was visualized with industrial X-ray computed tomography and digital image analysis techniques. The results showed that soil total porosity(? 100 ?m), total pore number, total throat number, and mean throat surface area increased significantly under wetting and drying cycles. Soil porosity, pore number and throat numberwithin each size class increased in the course of wetting and drying cycles. The coordination number, degree of anisotropy and fractal dimension were indicating an increase. In contrast, the mean shape factor, pore-throat ratio, and Euler-Poincaré number decreased due to wetting and drying cycles. These illustrated that the wetting and drying cycles made soil pore structure become more porous, continuous, heterogeneous and complex. It can thus be deduced that the water-level fluctuation would modify soil porosity, pore size distribution, and pore morphology in the Three Gorges Reservoir, which may have profound implications for soil processes, soil functions, and bank stability.
文摘Neutron radiography is one of radiography non-destructive testing.It is a valuable complementary of X and γ rays radiography.The present status and history of neutron radiography in China was described briefly,facilities of neutron radiography and their development were introduced in this paper.
文摘My camera lens is so illusionary that the authenticity of the Forbidden City is fading away. And my perspective is as narrow as an awl which slowly stings into the profundity of history... —Li
文摘Since the beginning of human civilization, the existence of a variety of production and life, etiquette and other social customs are obvious. The invention of photography is natural firstly used to the performance of various phenomena of human existence. Not until 1993 did Folk photography was formally proposed and was quickly accepted by the public. Folk photographer should have a certain amount of theoretical knowledge of folklore, ethnology, anthropology, and folklore should familiar with the laws of photography. Folk photographer should not only be able to skillfully use a variety of photographic techniques to create photographer, but also have the ability of folklore studies, which means a certain level of theory and master certain research methods. Folk photography creative process is a cultural experience and explores the process of discovery. Folk photography is methods and means to record, release and heritage attending profound traditional Chinese culture. Folk photography through a unique form of expression, with its visual image, embodies the academic value of folk history, the development of human history, cultural heritage and makes a positive contribution to the spread. In the 21st century, China' s social stable, economic development rapidly, which provide a good folk photography authoring environment. Folk photography range will also change with the development of folk and continuously expanding, concerns and reflections about the new folk themes have yet to be excavated, to meet the needs of social development.
基金supported by National Key Research and Development Program of China (Grant No. 2017YFC0601206)
文摘We picked new traveltime residual datasets in three frequency bands (0.02%). 1,0.1-0.8, and 0.8-2.0 Hz) for P-waves from 793 teleseismic events and two frequency bands (0.02-0.1 and 0.1-0.8 Hz) for S-waves from 310 teleseismic events, recorded by 389 permanent stations of the China National Seismic Network and 832 broadband stations of 10 temporary arrays deployed in the North China Craton (NCC) region. The final datasets are composed of 65628 P-arrivals and 47050 S-arrivals. Based on previous research and our team's 2012 tomographic work, we constructed new three-dimensional P-velocity and S- velocity models of the NCC through some improvements, such as augmenting a much denser station coverage in the western NCC, considering the incident angle effect in crustal correction and using a multi-frequency joint inversion tomographic technique. The new velocity models provide several salient features, from which we draw possible inferences on regional dynamic processes. We observed high-velocity anomalies in the mantle transition zone (MTZ). Obvious morphological het- erogeneities suggest buckling and/or fragmentation of the subducted Pacific slab, and some of the slab materials are visible below 660-kin discontinuities. The velocity structure of the eastern NCC is dominated by small-scale lateral heterogeneities. At shallow depths, high-velocity anomalies beneath the southern part of the eastern NCC and the Yanshan region likely represent a remnant of cratonic lithosphere, which may suggest that the NCC destruction is spatially non-uniform. We also detected a high-velocity anomaly in the Sulu Orogen extending downward to -300 kin, which is seemingly controlled by the Tan-Lu Fault. The northern boundary of this anomaly spatially coincides with the Yantai-Qingdao-Wulian Fault, and is likely a remnant of the Yangtze cratonic lithosphere subducting northwestward. Significant low-velocity anomalies imaged beneath the central NCC show a spatial discordance between their northern and southern parts. The northern low-velocity anomaly extends downward to the top of MTZ with a lateral NW-SE strike, whereas the southern one tapers off at -200-300 kin. Low-velocity anomalies are present beneath the Phanerozoic orogenic belts surrounding the NCC, the Paleoproterozoic Trans-North China Orogen, and the Tan-Lu Fault. This feature not only shows excellent spatial correlation with the orogens at the surface, it also exhibits a consistent vertical continuity in a depth range of 60-250 km. This intriguing feature suggests that the collisional orogenic belts and Tan-Lu Fault are inherited weak zones, which may play a key role in craton destruction. By combining multidisciplinary results in this area, we suggest that the spatial heterogeneities associated with the NCC destruction most likely result from the combined effects of a spatially non-uniform distribution of wet upwellings triggered by the subducted Pacific slab and pre-existing weak zones in the eratonic lithosphere.
基金This work was supported by the National Key Basic Research Project (Grant No. G1998040700)and partly by US National Science Foundation grant (EAR9614616). Contribution No. 01FE2013, Institute of Geophysics, China Seismological Bureau. We sincerely than
文摘39473 Pn travel times are inverted to tomographically image both lateral variation and anisotropy of uppermost mantle velocities beneath China continent. The result indicates that the overall average Pn velocity of uppermost mantle in the studied region is 8.0 km/s and the regional velocity fluctuation varies from ?0.30 km/s to +0.35 km/s. Pn velocities higher than 8.2 km/s are found in the regions surrounding Qingzang Plateau, such as Junggar Basin, Tarim Basin, Qaidam Basin and Sichun Basin. Pn velocities slightly lower than the average are found in western Sichuan and Yunnan, Shanxi Graben and Bohai Bay region. A Pn velocity as low as 7.8 km/s may exist in the region striding the boundary between Guangxi and Guangdong provinces. In general, Pn velocity in tectonically stable region like cratonic platform tends to be high, while that in tectonically active region tends to be low. The regions in compressive setting usually show higher Pn velocity, while extensional basins or grabens generally display lower one. Anisotropy of Pn velocity is seen in some regions. In the southeastern region of Qingzang Plateau the directions of fastest Pn velocity show a rotation pattern, which may be related to southeastward escape of the plateau material due to the collision and compression of Indian Plate to Asia along Himalaya arc. Notable anisotropy also exists around Bohai Bay region, likely indicating crustal extending and possible magma activity therein.
基金NCFC Super Parallel Computation Environment, NetworkInformation Center, Chinese Academy of Sciences. This work was supported by the National Natural Science Foundation of China (Grant No. 49474214).
文摘Three-dimensional velocity images of the crust and upper mantlebeneath orogenic belts and adjacent basins of the northwestern continent of China are reconstructed by seismic tomography, based on arrival data of P wave recorded in seismic networks in Xinjiang, Qinghai, Gansu of China and Kyrgyzstan. The velocity images of upper crust demonstrate the tectonic framework on the ground surface. High velocities are observed beneath orogenic belts, and low velocities are observed in the basins and depressions that are obviously related to unconsolidated sediments. The velocity image in mid-crust maintains the above features, and in addition low velocities appear in some earthquake regions and a low velocity boundary separates the western Tianshan Mts. from eastern Tianshan Mts. The orogenic belts and the northern Tibetan plateau have a Moho depth over 50 km, whereas the depths of the Moho in basins and depressions are smaller than 50 km. The velocity images of upper mantle clearly reveal the colliding relationship and location of deep boundaries of the continental blocks in northwestern China, indicating a weakness of the upper mantle structure of orogenic belts. The top depth of upper mantle asthenosphere varies from place to place. It seems shallower under the northern Tibetan plateau, Altay and Qilian Mts., and deeper under the Tarim and Tianshan regions. Hot mantle probably rose to the bottom of some orogenic belts along tectonic boundaries when continental blocks collided to each other. Therefore their dynamic features are closely correlated to the formation and evolution of orogenic belts in northwestern China.