Facies and fracture network modeling need robust, realistic and multi scale methods that can extract and reproduce complex relations in geological structures. Multi Point Statistic (MPS) algorithms can be used to mode...Facies and fracture network modeling need robust, realistic and multi scale methods that can extract and reproduce complex relations in geological structures. Multi Point Statistic (MPS) algorithms can be used to model these high order relations from a visually and statistically explicit model, a training image. FILTERSIM as a pattern based MPS method attracts much attention. It decreases the complexity of computation, accelerates search process and increases CPU per-formance compare to other MPS methods by transferring training image patterns to a lower dimensional space. The results quality is not however as satisfactory. This work presents an improved version of FILTERSIM in which pattern extraction, persisting and pasting steps are modified to enhance visual quality and structures continuity in the realiza-tions. Examples shown in this paper give visual appealing results for the reconstruction of stationary complex struc-tures.展开更多
Aberrant right subclavian artery(arteria lusoria) is the most common congenital root anomaly, remaining asymptomatic in most cases. Nevertheless, some of the 20%-40% of those affected present tracheo-esophageal sympto...Aberrant right subclavian artery(arteria lusoria) is the most common congenital root anomaly, remaining asymptomatic in most cases. Nevertheless, some of the 20%-40% of those affected present tracheo-esophageal symptoms. We report on a 6-year-old previously healthy girl presenting with progressive dysphagia over 4 wk. Diagnostics including barium swallow, echocardiography and magnetic resonance angiography(MRA) revealed a retro-esophageal compression by an aberrant right subclavian artery. Despite the successful, uneventful transposition of this arteria lusoria to the right common carotid via right-sided thoracotomy, the girl was suffering from persisting dysphagia. Another barium swallow showed the persistent compression of the esophagus on the level where the arteria lusoria had originated. As MRA showed no evidence of a significant re-obstruction by the transected vascular stump, we suspected a persisting ligamentum arteriosum. After a second surgical intervention via left-sided thoracotomy consisting of transecting the obviously persisting ligamentum and shortening the remaining arterial stump of the aberrant right subclavian artery, the patient recovered fully. In this case report we discuss the potential relevance of a persisting ligamentum arteriosum for patients with leftaortic arch suffering from dysphagia lusoria and rational means of diagnosing, as well as the surgical options to prevent re-do surgery.展开更多
It has been certificated that corridors can help giant pandas to keep their habitat from fragmenting. However there are still losses during the process of moving along corridors. In this study, a mathematical model wi...It has been certificated that corridors can help giant pandas to keep their habitat from fragmenting. However there are still losses during the process of moving along corridors. In this study, a mathematical model with Allee effect is carried out to describe the diffusion of giant pandas between n patches. Some criteria are obtained to keep the system persisting. It is proved that the system has a unique positive w-periodic solution which is globally asymptotically stable. The ecological meanings of these findings are discussed following the results. And some numerical simulations in the Qinling Mountain giant panda nature reservation area are also presented in the end.展开更多
On May 25, George Floyd, an African American, died after a policeman knelt on his neck while arresting him. Floyd’s death ignited anger and chaos across the U.S. over the unfair treatment of African Americans by the ...On May 25, George Floyd, an African American, died after a policeman knelt on his neck while arresting him. Floyd’s death ignited anger and chaos across the U.S. over the unfair treatment of African Americans by the police. In an interview with Beijing Review, Jon Taylor, Chair of the Department of Political Science and Geography and professor of political science at the University of Texas at San Antonio, shares his observations on the causes of the permanent racism in U.S. society.展开更多
Recently, the Press Center of China National Textile &Apparel Council issued the information about the economicoperation of the textile industry in the first quarter. It couldbe seen from the main economic indexes...Recently, the Press Center of China National Textile &Apparel Council issued the information about the economicoperation of the textile industry in the first quarter. It couldbe seen from the main economic indexes that, since展开更多
文摘Facies and fracture network modeling need robust, realistic and multi scale methods that can extract and reproduce complex relations in geological structures. Multi Point Statistic (MPS) algorithms can be used to model these high order relations from a visually and statistically explicit model, a training image. FILTERSIM as a pattern based MPS method attracts much attention. It decreases the complexity of computation, accelerates search process and increases CPU per-formance compare to other MPS methods by transferring training image patterns to a lower dimensional space. The results quality is not however as satisfactory. This work presents an improved version of FILTERSIM in which pattern extraction, persisting and pasting steps are modified to enhance visual quality and structures continuity in the realiza-tions. Examples shown in this paper give visual appealing results for the reconstruction of stationary complex struc-tures.
文摘Aberrant right subclavian artery(arteria lusoria) is the most common congenital root anomaly, remaining asymptomatic in most cases. Nevertheless, some of the 20%-40% of those affected present tracheo-esophageal symptoms. We report on a 6-year-old previously healthy girl presenting with progressive dysphagia over 4 wk. Diagnostics including barium swallow, echocardiography and magnetic resonance angiography(MRA) revealed a retro-esophageal compression by an aberrant right subclavian artery. Despite the successful, uneventful transposition of this arteria lusoria to the right common carotid via right-sided thoracotomy, the girl was suffering from persisting dysphagia. Another barium swallow showed the persistent compression of the esophagus on the level where the arteria lusoria had originated. As MRA showed no evidence of a significant re-obstruction by the transected vascular stump, we suspected a persisting ligamentum arteriosum. After a second surgical intervention via left-sided thoracotomy consisting of transecting the obviously persisting ligamentum and shortening the remaining arterial stump of the aberrant right subclavian artery, the patient recovered fully. In this case report we discuss the potential relevance of a persisting ligamentum arteriosum for patients with leftaortic arch suffering from dysphagia lusoria and rational means of diagnosing, as well as the surgical options to prevent re-do surgery.
基金This work is supported by the National Science Foundation of China （No. Z13060）, Beijing Higher Education Young Elite Teacher Project of China （No. YETP1655）, Beijing Talents Fund （No. 2012D005017000003）, Simulation and Evaluation of Indoor Environmental Comfort Improvement （No. 2013BAJ02B0404） and Youth Foundation of Beijing University of Civil Engineering and Architecture （No. Z12082）.
文摘It has been certificated that corridors can help giant pandas to keep their habitat from fragmenting. However there are still losses during the process of moving along corridors. In this study, a mathematical model with Allee effect is carried out to describe the diffusion of giant pandas between n patches. Some criteria are obtained to keep the system persisting. It is proved that the system has a unique positive w-periodic solution which is globally asymptotically stable. The ecological meanings of these findings are discussed following the results. And some numerical simulations in the Qinling Mountain giant panda nature reservation area are also presented in the end.
文摘On May 25, George Floyd, an African American, died after a policeman knelt on his neck while arresting him. Floyd’s death ignited anger and chaos across the U.S. over the unfair treatment of African Americans by the police. In an interview with Beijing Review, Jon Taylor, Chair of the Department of Political Science and Geography and professor of political science at the University of Texas at San Antonio, shares his observations on the causes of the permanent racism in U.S. society.
文摘Recently, the Press Center of China National Textile &Apparel Council issued the information about the economicoperation of the textile industry in the first quarter. It couldbe seen from the main economic indexes that, since
