The Editor welcomes submissions for possible publication in the Letters to the Editor section.Letters commenting on an article published in the Journal or other interesting pieces will be considered if they are receiv...The Editor welcomes submissions for possible publication in the Letters to the Editor section.Letters commenting on an article published in the Journal or other interesting pieces will be considered if they are received within 6 weeks of the time the article was published.展开更多
To the Editor:We read with great interest the recent paper by Baran and colleagues,[1]published in the journal of Hepatobiliary Pancreatic Diseases International.The authors presented nails abnormalities in a 65-year-...To the Editor:We read with great interest the recent paper by Baran and colleagues,[1]published in the journal of Hepatobiliary Pancreatic Diseases International.The authors presented nails abnormalities in a 65-year-old woman with cryptogenic cirrhosis and hepatocellular carcinoma and described them as Terry’s nails.Whether they were Terry’s nails remains controversial,at least far away from展开更多
Aims Observer error is an unavoidable aspect of vegetation surveys involving human observers.We quantified four components of interobserver error associated with long-term monitoring of prairie vegetation:overlooking ...Aims Observer error is an unavoidable aspect of vegetation surveys involving human observers.We quantified four components of interobserver error associated with long-term monitoring of prairie vegetation:overlooking error,misidentification error,cautious error and estimation error.We also evaluated the association of plot size with pseudoturnover due to observer error,and how documented pseudochanges in species composition and abundance compared with recorded changes in the vegetation over a 4-year interval.Methods This study was conducted at Tallgrass Prairie National Preserve,Kansas.Monitoring sites contained 10 plots;each plot consisted of a series of four nested frames(0.01,0.1,1 and 10 m^(2)).The herbaceous species present were recorded in each of the nested frames,and foliar cover was visually estimated within seven cover categories at the 10 m^(2)spatial scale only.Three hundred total plots(30 sites)were surveyed,and 28 plots selected at random were resurveyed to assess observer error.Four surveyors worked in teams of two.Important Findings At the 10 m^(2)spatial scale,pseudoturnover resulting from overlooking error averaged 18.6%,compared with 1.4%resulting from misidentification error and 0.6%resulting from cautious error.Pseudoturnover resulting from overlooking error increased as plot size decreased,although relocation error likely played a role.Recorded change in species composition over a 4-year interval(excluding potential misidentification error and cautious error)was 30.7%,which encompassed both pseudoturnover due to overlooking error and actual change.Given a documented overlooking error rate of 18.6%,this suggests the actual change for the 4-year period was only 12.1%.For estimation error,26.2%of the time a different cover class was recorded.Over the 4-year interval,46.9%of all records revealed different cover classes,suggesting that 56%of the records of change in cover between the two time periods were due to observer error.展开更多
Within multicellular plants, cells constantly communicate with their neighbors and even distant cells. A cell may produce chemical signals, such as peptides and small molecules, and perceive chemical signals from othe...Within multicellular plants, cells constantly communicate with their neighbors and even distant cells. A cell may produce chemical signals, such as peptides and small molecules, and perceive chemical signals from other cells. Thus, signaling chemicals mediate the exchange of information between cells. There is a simpler and faster way for cells to communicate, i.e., a cell can mechanically nudge its neighbors to send a signal. However, mechanical force is often ignored by biologists, partially due to the difficulty in directly visualizing the force, in contrast to visual detection of signaling molecules.展开更多
文摘The Editor welcomes submissions for possible publication in the Letters to the Editor section.Letters commenting on an article published in the Journal or other interesting pieces will be considered if they are received within 6 weeks of the time the article was published.
文摘To the Editor:We read with great interest the recent paper by Baran and colleagues,[1]published in the journal of Hepatobiliary Pancreatic Diseases International.The authors presented nails abnormalities in a 65-year-old woman with cryptogenic cirrhosis and hepatocellular carcinoma and described them as Terry’s nails.Whether they were Terry’s nails remains controversial,at least far away from
基金funded by the National Park Service Inventory and Monitoring Program.
文摘Aims Observer error is an unavoidable aspect of vegetation surveys involving human observers.We quantified four components of interobserver error associated with long-term monitoring of prairie vegetation:overlooking error,misidentification error,cautious error and estimation error.We also evaluated the association of plot size with pseudoturnover due to observer error,and how documented pseudochanges in species composition and abundance compared with recorded changes in the vegetation over a 4-year interval.Methods This study was conducted at Tallgrass Prairie National Preserve,Kansas.Monitoring sites contained 10 plots;each plot consisted of a series of four nested frames(0.01,0.1,1 and 10 m^(2)).The herbaceous species present were recorded in each of the nested frames,and foliar cover was visually estimated within seven cover categories at the 10 m^(2)spatial scale only.Three hundred total plots(30 sites)were surveyed,and 28 plots selected at random were resurveyed to assess observer error.Four surveyors worked in teams of two.Important Findings At the 10 m^(2)spatial scale,pseudoturnover resulting from overlooking error averaged 18.6%,compared with 1.4%resulting from misidentification error and 0.6%resulting from cautious error.Pseudoturnover resulting from overlooking error increased as plot size decreased,although relocation error likely played a role.Recorded change in species composition over a 4-year interval(excluding potential misidentification error and cautious error)was 30.7%,which encompassed both pseudoturnover due to overlooking error and actual change.Given a documented overlooking error rate of 18.6%,this suggests the actual change for the 4-year period was only 12.1%.For estimation error,26.2%of the time a different cover class was recorded.Over the 4-year interval,46.9%of all records revealed different cover classes,suggesting that 56%of the records of change in cover between the two time periods were due to observer error.
基金National Natural Science Foundation of China Grants 31825002, 31430010, 31861143021, and 31861130355aRoyal Society Newt on Advanced Fellowship (award NAF\R1\180125).
文摘Within multicellular plants, cells constantly communicate with their neighbors and even distant cells. A cell may produce chemical signals, such as peptides and small molecules, and perceive chemical signals from other cells. Thus, signaling chemicals mediate the exchange of information between cells. There is a simpler and faster way for cells to communicate, i.e., a cell can mechanically nudge its neighbors to send a signal. However, mechanical force is often ignored by biologists, partially due to the difficulty in directly visualizing the force, in contrast to visual detection of signaling molecules.
