This work deals with the evolution of carbon isotope composition in the Luoyixi （罗依溪） Section, a candidate of the Global Standard Stratotype-section and Point （GSSP）, defining the base of the as-yet-undefined s...This work deals with the evolution of carbon isotope composition in the Luoyixi （罗依溪） Section, a candidate of the Global Standard Stratotype-section and Point （GSSP）, defining the base of the as-yet-undefined seventh stage of Cambrian System at the first appearance of the cosmopolitan agnostoid Lejopyge iaevigata. This level is favored in a vote of International Subcommission on Cambrian Stratigraphy （ISCS） as the biohorizon for defining the base of a global stage. Two hundred and sixty-four samples for carbon and oxygen isotope analysis have been collected from the carbonate successions at an interval of 0.25 to 0.5 m in this section. Results of the carbon isotope data exhibit a remarkable disciplinarian trend. The pattern of the carbon isotope evolution is gently undulant with a relatively long period during the underlying Drumian Stage, and then the values of δ13C fluctuate sharply with a short period in provisional seventh stage. The onset of sharp fluctuation in the δ13C values begins at the proposed GSSP level, defining the base of the global seventh stage, where δ13C values change from a gentle trend to a sharp trend. Distinct covariant-relationships among δ13C,δ18O, and sea level fluctuations suggest that a warming change in paleoclimate took place during the early global seventh stage, which led to a positive shift in δ13C values.展开更多
This paper introduces a practical solving scheme of gradetransition trajectory optimization(GTTO) problems under typical certificate-checking–updating framework. Due to complicated kinetics of polymerization,differen...This paper introduces a practical solving scheme of gradetransition trajectory optimization(GTTO) problems under typical certificate-checking–updating framework. Due to complicated kinetics of polymerization,differential/algebraic equations(DAEs) always cause great computational burden and system non-linearity usually makes GTTO non-convex bearing multiple optima. Therefore, coupled with the three-stage decomposition model, a three-section algorithm of dynamic programming(TSDP) is proposed based on the general iteration mechanism of iterative programming(IDP) and incorporated with adaptivegrid allocation scheme and heuristic modifications. The algorithm iteratively performs dynamic programming with heuristic modifications under constant calculation loads and adaptively allocates the valued computational resources to the regions that can further improve the optimality under the guidance of local error estimates. TSDP is finally compared with IDP and interior point method(IP) to verify its efficiency of computation.展开更多
This paper briefly summarizes an officially ratified Global Standard Stratotype-section and Point （GSSP） and a proposed GSSP for global stages of the Cambrian System. The Luoyixi section near Luoyixi town, Guzhang, ...This paper briefly summarizes an officially ratified Global Standard Stratotype-section and Point （GSSP） and a proposed GSSP for global stages of the Cambrian System. The Luoyixi section near Luoyixi town, Guzhang, northwestern Hunan is ratified as the boundary stratotype for the base of the global Guzhangian Stage, which is the upmost stage of an unnamed series termed provisionally as Cambrian Series 3. The GSSP position lies 121.3 m above the base of the Huaqiao Formation in the section, coinciding with the first appearance of the cosmopolitan agnostoid trilobite Lejopyge leavigata.The Duibian B section at Duibian village, Jiangshan, western Zhejiang, is proposed as the boundary stratotype for the base of the proposed global Jiangshanian Stage that is the second stage of the Furongian Series. The proposed GSSP position lies 108.12 m above the base of the Huayansi Formation in the section, coinciding with the first appearance of the cosmopolitan agnostoid trilobite Agnostotes orientalius. This horizon is also with the first appearance of the cosmopolitan polymerid trilobite lrvingella angustilimbata.展开更多
We describe new material of three-dimensionally phosphatized small shelly fossils Acanthocassis and Xinlispina gen.nov.from the Fortunian Stage（early Cambrian） of southern Shaanxi and northern Sichuan Provinces.The ...We describe new material of three-dimensionally phosphatized small shelly fossils Acanthocassis and Xinlispina gen.nov.from the Fortunian Stage（early Cambrian） of southern Shaanxi and northern Sichuan Provinces.The new materials allow description of the delicate morphology of these skeletons, and also their skeletogenesis.Acanthocassis and Xinlispina have comparable morphological features： a main branch and radially arranged sub-branches.They differ from each other in many details, e.g., the presence of a single central branch only in Xinlispina, and the presence of small nodes only in Acanthocassis.Acanthocassis cannot be a naked anthopolyp or hydropolyp because of the more-or-less stiffened cuticle and the absence of a mouth.Acanthocassisand Xinlispina differ from coeval sponge spicules and chancelloriid sclerites and rosettes of crossed pedicellariae of echinoderms, and might be cuticular ornaments of animals of unclear affinities.They occur in the first small shelly fossil assemblage zone, and could be adopted as auxiliary fossils for biostratigraphic correlation in southern China.展开更多
Background: Frozen section (FS) has a valuable role in the diagnosis of ovarian tumors. It is considered a pivotal point in guiding the surgical therapy, particularly in premenopausal women. In postmenopausal women, i...Background: Frozen section (FS) has a valuable role in the diagnosis of ovarian tumors. It is considered a pivotal point in guiding the surgical therapy, particularly in premenopausal women. In postmenopausal women, it may be required as well to avoid unnecessary surgical staging in benign ovarian tumors. Aim: This study aims to evaluate the accuracy of intraoperative frozen section in ovarian neoplasms in postmenopausal women. Materials and Methods: A retrospective analysis was done for intraoperative FS for suspected ovarian neoplasms. The study was conducted in Oncology Center, Mansoura University from March 2008 to December 2014. The frozen and paraffin section reports were compared, and overall accuracy, sensitivity, specificity, positive and negative predictive values were determined. Results: The study included 105 patients and the overall accuracy of FS in determining malignancy was 81.7%. The sensitivity for malignant tumors was 75.32% with specificity of 100%. For benign tumors, the sensitivity and specificity were 100% and 93%, respectively. Borderline tumors had the lowest sensitivity of 100% with specificity of 95.19%. Conclusion: The present study concurs that frozen section is an accurate test for diagnosis of benign and malignant tumors in postmenopausal women thus determining the extent of surgery done for them. On the other hand, accuracy rates for borderline tumors are low.展开更多
基金the National Natural Science Foundation of China (Nos. 40672023, 40332018)Chinese Academy of Sciences (KZCX2-YW-122) and the Major Basic Research Project of MST (2006CB806400).
文摘This work deals with the evolution of carbon isotope composition in the Luoyixi （罗依溪） Section, a candidate of the Global Standard Stratotype-section and Point （GSSP）, defining the base of the as-yet-undefined seventh stage of Cambrian System at the first appearance of the cosmopolitan agnostoid Lejopyge iaevigata. This level is favored in a vote of International Subcommission on Cambrian Stratigraphy （ISCS） as the biohorizon for defining the base of a global stage. Two hundred and sixty-four samples for carbon and oxygen isotope analysis have been collected from the carbonate successions at an interval of 0.25 to 0.5 m in this section. Results of the carbon isotope data exhibit a remarkable disciplinarian trend. The pattern of the carbon isotope evolution is gently undulant with a relatively long period during the underlying Drumian Stage, and then the values of δ13C fluctuate sharply with a short period in provisional seventh stage. The onset of sharp fluctuation in the δ13C values begins at the proposed GSSP level, defining the base of the global seventh stage, where δ13C values change from a gentle trend to a sharp trend. Distinct covariant-relationships among δ13C,δ18O, and sea level fluctuations suggest that a warming change in paleoclimate took place during the early global seventh stage, which led to a positive shift in δ13C values.
基金Supported by the National Basic Research Program of China(2012CB720500)the National High Technology Research and Development Program of China(2013AA040702)
文摘This paper introduces a practical solving scheme of gradetransition trajectory optimization(GTTO) problems under typical certificate-checking–updating framework. Due to complicated kinetics of polymerization,differential/algebraic equations(DAEs) always cause great computational burden and system non-linearity usually makes GTTO non-convex bearing multiple optima. Therefore, coupled with the three-stage decomposition model, a three-section algorithm of dynamic programming(TSDP) is proposed based on the general iteration mechanism of iterative programming(IDP) and incorporated with adaptivegrid allocation scheme and heuristic modifications. The algorithm iteratively performs dynamic programming with heuristic modifications under constant calculation loads and adaptively allocates the valued computational resources to the regions that can further improve the optimality under the guidance of local error estimates. TSDP is finally compared with IDP and interior point method(IP) to verify its efficiency of computation.
基金supported by the Ministry of Science and Technology of China (2006FY120300)the State Key Laboratory of Palaeobiology and Stratigraphy (20091103)funded by the National Natural Science Foundation of China (40072003, 40023002, 40332018, 40672023, 40602002)
文摘This paper briefly summarizes an officially ratified Global Standard Stratotype-section and Point （GSSP） and a proposed GSSP for global stages of the Cambrian System. The Luoyixi section near Luoyixi town, Guzhang, northwestern Hunan is ratified as the boundary stratotype for the base of the global Guzhangian Stage, which is the upmost stage of an unnamed series termed provisionally as Cambrian Series 3. The GSSP position lies 121.3 m above the base of the Huaqiao Formation in the section, coinciding with the first appearance of the cosmopolitan agnostoid trilobite Lejopyge leavigata.The Duibian B section at Duibian village, Jiangshan, western Zhejiang, is proposed as the boundary stratotype for the base of the proposed global Jiangshanian Stage that is the second stage of the Furongian Series. The proposed GSSP position lies 108.12 m above the base of the Huayansi Formation in the section, coinciding with the first appearance of the cosmopolitan agnostoid trilobite Agnostotes orientalius. This horizon is also with the first appearance of the cosmopolitan polymerid trilobite lrvingella angustilimbata.
基金supported by the National Natural Science Foundation of China (41072012 and 41102003)the State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (113115 and 20132107)+2 种基金the Key Project of Central University Fund (CHD2012ZD017)College Students’ Innovative Entrepreneurial Training Program (201410710144 and 201410710105)The Ninth "Challenge Cup" Competition of College Students’ Extracurricular Academic and Technological Achievements, Chang’an University
文摘We describe new material of three-dimensionally phosphatized small shelly fossils Acanthocassis and Xinlispina gen.nov.from the Fortunian Stage（early Cambrian） of southern Shaanxi and northern Sichuan Provinces.The new materials allow description of the delicate morphology of these skeletons, and also their skeletogenesis.Acanthocassis and Xinlispina have comparable morphological features： a main branch and radially arranged sub-branches.They differ from each other in many details, e.g., the presence of a single central branch only in Xinlispina, and the presence of small nodes only in Acanthocassis.Acanthocassis cannot be a naked anthopolyp or hydropolyp because of the more-or-less stiffened cuticle and the absence of a mouth.Acanthocassisand Xinlispina differ from coeval sponge spicules and chancelloriid sclerites and rosettes of crossed pedicellariae of echinoderms, and might be cuticular ornaments of animals of unclear affinities.They occur in the first small shelly fossil assemblage zone, and could be adopted as auxiliary fossils for biostratigraphic correlation in southern China.
文摘Background: Frozen section (FS) has a valuable role in the diagnosis of ovarian tumors. It is considered a pivotal point in guiding the surgical therapy, particularly in premenopausal women. In postmenopausal women, it may be required as well to avoid unnecessary surgical staging in benign ovarian tumors. Aim: This study aims to evaluate the accuracy of intraoperative frozen section in ovarian neoplasms in postmenopausal women. Materials and Methods: A retrospective analysis was done for intraoperative FS for suspected ovarian neoplasms. The study was conducted in Oncology Center, Mansoura University from March 2008 to December 2014. The frozen and paraffin section reports were compared, and overall accuracy, sensitivity, specificity, positive and negative predictive values were determined. Results: The study included 105 patients and the overall accuracy of FS in determining malignancy was 81.7%. The sensitivity for malignant tumors was 75.32% with specificity of 100%. For benign tumors, the sensitivity and specificity were 100% and 93%, respectively. Borderline tumors had the lowest sensitivity of 100% with specificity of 95.19%. Conclusion: The present study concurs that frozen section is an accurate test for diagnosis of benign and malignant tumors in postmenopausal women thus determining the extent of surgery done for them. On the other hand, accuracy rates for borderline tumors are low.
