Neurodegenerative diseases are a leading cause of disability worldwide,and despite significant resources put toward the discovery of potential therapeutic targets,there are currently no effective treatments.The rise o...Neurodegenerative diseases are a leading cause of disability worldwide,and despite significant resources put toward the discovery of potential therapeutic targets,there are currently no effective treatments.The rise of methods to derive and propagate stem cells in vitro offered展开更多
The Global Boundary Stratotype Section and Point （GSSP） for the Katian Stage of the Upper Ordovician Series is defined as the 4.0 m-level above the base of the Bigfork Chert in the Black Knob Ridge section, southeas...The Global Boundary Stratotype Section and Point （GSSP） for the Katian Stage of the Upper Ordovician Series is defined as the 4.0 m-level above the base of the Bigfork Chert in the Black Knob Ridge section, southeastern Oklahoma. This point in this section is coincident with the first appearance of the graptolite Diplacanthograptus caudatus, which has proved to be a reliable datum for precise worldwide correlation. The FAD ofD. caudatus occurs very near the first occurrences of the graptolites D. lanceolatus, Co.rynoides americanus, Orthograptus pageanus, O. quadrimucronatus, Dicranograptus hians, and Neurograptus margaritatus. This rapid succession of fossil species appearance events provides a secure basis for identification of the base of the Katian Stage of the Upper Ordovician Series and for its global chronostratigraphic correlation.展开更多
基金supported by the NIH (NEI grant RO1 EY 018132,Kirschstein-NRSA 4T32HD007505-20)
文摘Neurodegenerative diseases are a leading cause of disability worldwide,and despite significant resources put toward the discovery of potential therapeutic targets,there are currently no effective treatments.The rise of methods to derive and propagate stem cells in vitro offered
基金Acknowledgments This work was supported by National Science Foundation grant EAR - 0106844 to D. Goldman and Estonian Science Foundation grant ETF - 5922 to J. Nōlvak. We would like to thank S.C. Finney for showing us the Black Knob Ridge section, suggesting its potential as a GSSP, and critically reviewing previous versions of the manuscript.
文摘The Global Boundary Stratotype Section and Point （GSSP） for the Katian Stage of the Upper Ordovician Series is defined as the 4.0 m-level above the base of the Bigfork Chert in the Black Knob Ridge section, southeastern Oklahoma. This point in this section is coincident with the first appearance of the graptolite Diplacanthograptus caudatus, which has proved to be a reliable datum for precise worldwide correlation. The FAD ofD. caudatus occurs very near the first occurrences of the graptolites D. lanceolatus, Co.rynoides americanus, Orthograptus pageanus, O. quadrimucronatus, Dicranograptus hians, and Neurograptus margaritatus. This rapid succession of fossil species appearance events provides a secure basis for identification of the base of the Katian Stage of the Upper Ordovician Series and for its global chronostratigraphic correlation.
