Four wetland maps for all China have been produced,based on Landsat and CBERS-02B remote sensing data between 1978 and 2008 (1978,1990,2000 and 2008).These maps were mainly developed by manual interpretation and valid...Four wetland maps for all China have been produced,based on Landsat and CBERS-02B remote sensing data between 1978 and 2008 (1978,1990,2000 and 2008).These maps were mainly developed by manual interpretation and validated by substantial field investigation in 2009.Based on these maps,we analyzed the 2008 wetland distribution in China and discussed wetland changes and their drivers over the past 30 years.(i) There were about 324097 km 2 of wetlands in 2008,for which inland marshes or swamps were the most common wetland type (35%),with lakes (26%) second.Most of the wetlands were in Heilongjiang,Inner Mongolia,Qinghai and Tibet,occupying about 55% of the national wetland area.(ii) From 1978 to 2008,China's wetland area continually and significantly decreased,by about 33% based on changes in the wetland map.This was in sharp contrast to the increase in artificial wetlands,which increased by about 122%.Inland marshes accounted for the main loss of total wetlands from 1978 to 2000.From 2000 through 2008,riverine and lacustrine wetlands constituted the main wetland loss.Fortunately however,the rate of wetland loss decreased from 5523 to 831 km 2 /a.(iii) The change ratio of lost natural wetlands (including inland and coastal wetlands) to non-wetlands has decreased slightly over the past 30 years.From 1978 to 1990,nearly all natural wetlands (98%) lost were transformed into non-wetlands.However,the ratio declined to 86% from 1990 to 2000,and to 77% from 2000 to 2008.(iv) All Chinese provinces were divided into three groups according to patterns of wetland changes,which could relate to the driving forces of such changes.Tibet was completely different from other provinces,as it was one representative example in which there was a net wetland increase,because of global warming and decreased human activity since 1990.Increased economic development caused considerable wetland loss in most eastern provinces,and artificial wetlands increased.展开更多
Dear Editor,In 2005,the current commonly used rice reference genome(Oryza sativa ssp.japonica cv.Nipponbare)was initially released by the International Rice Genome Sequencing Project(International Rice Genome Sequenci...Dear Editor,In 2005,the current commonly used rice reference genome(Oryza sativa ssp.japonica cv.Nipponbare)was initially released by the International Rice Genome Sequencing Project(International Rice Genome Sequencing Project,2005).Thereafter,the reference genome was further updated in 2013 with improved genome assembly(IRGSP-1.0)and gene annotations(MSU7,RAP-DB)(Kawahara et al.,2013;Sakai et al.,2013).In the past 10 years,this reference has been serving as one of the most important genetic resources for subsequent rice functional genomics efforts.As several rice genomes had been assembled into gapless chromosomes with only 2–5 telomeres absent(Li et al.,2021;Song et al.,2021;Zhang et al.,2022),the IRGSP1.0 and its annotations still performed as the most widely used reference.However,limitations of sequencing technology and intricate genomic organization led to an under-representation of complex regions in this reference,leaving a total of 72 major gaps(including 19 telomeres),167 minor gaps,and 779 unknown bases(Kawahara et al.,2013),with an estimated length of3%of the genome unsolved.展开更多
The Jiao Tong University Spectroscopic Telescope(JUST)is a 4.4-meter f/6.0 segmented-mirror telescope dedicated to spectroscopic observations.The JUST primary mirror is composed of 18 hexagonal segments,each with a di...The Jiao Tong University Spectroscopic Telescope(JUST)is a 4.4-meter f/6.0 segmented-mirror telescope dedicated to spectroscopic observations.The JUST primary mirror is composed of 18 hexagonal segments,each with a diameter of 1.1 m.JUST provides two Nasmyth platforms for placing science instruments.One Nasmyth focus fits a field of view of 10′and the other has an extended field of view of 1.2°with correction optics.A tertiary mirror is used to switch between the two Nasmyth foci.JUST will be installed at a site at Lenghu in Qinghai Province,China,and will conduct spectroscopic observations with three types of instruments to explore the dark universe,trace the dynamic universe,and search for exoplanets:(1)a multi-fiber(2000 fibers)medium-resolution spectrometer(R=4000-5000)to spectroscopically map galaxies and large-scale structure;(2)an integral field unit(IFU)array of 500 optical fibers and/or a long-slit spectrograph dedicated to fast follow-ups of transient sources for multi-messenger astronomy;(3)a high-resolution spectrometer(R~100000)designed to identify Jupiter analogs and Earth-like planets,with the capability to characterize the atmospheres of hot exoplanets.展开更多
Neutrinos from core-collapse supernovae are essential for understanding neutrino physics and stellar evolution.Dual-phase xenon dark matter detectors can be used to track explosions of galactic supernovae by detecting...Neutrinos from core-collapse supernovae are essential for understanding neutrino physics and stellar evolution.Dual-phase xenon dark matter detectors can be used to track explosions of galactic supernovae by detecting neutrinos through coherent elastic neutrino-nucleus scatterings.In this study,a variation of progenitor masses and explosion models are assumed to predict neutrino fluxes and spectra,which result in the number of expected neutrino events ranging from 6.6 to 13.7 at a distance of 10 kpc over a 10-s duration with negligible backgrounds at PandaX-4T.Two specialized triggering alarms for monitoring supernova burst neutrinos are built.The efficiency of detecting supernova explosions at various distances in the Milky Way is estimated.These alarms will be implemented in the real-time supernova monitoring system at PandaX-4T in the near future,which will provide supernova early warnings for the astronomical community.展开更多
Rice(Oryza sativa)is a significant crop worldwide with a genome shaped by various evolutionary factors.Rice centromeres are crucial for chromosome segregation,and contain some unreported genes.Due to the diverse and c...Rice(Oryza sativa)is a significant crop worldwide with a genome shaped by various evolutionary factors.Rice centromeres are crucial for chromosome segregation,and contain some unreported genes.Due to the diverse and complex centromere region,a comprehensive understanding of rice centromere structure and function at the population level is needed.We constructed a high-quality centromere map based on the rice super pangenome consisting of a 251-accession panel comprising both cultivated and wild species of Asian and African rice.We showed that rice centromeres have diverse satellite repeat CentO,which vary across chromosomes and subpopulations,reflecting their distinct evolutionary patterns.We also revealed that long terminal repeats(LTRs),especially young Gypsy-type LTRs,are abundant in the peripheral CentO-enriched regions and drive rice centromere expansion and evolution.Furthermore,high-quality genome assembly and complete telomere-to-telomere(T2T)reference genome enable us to obtain more centromeric genome information despite mapping and cloning of centromere genes being challenging.We investigated the association between structural variations and gene expression in the rice centromere.A centromere gene,OsMAB,which positively regulates rice tiller number,was further confirmed by expression quantitative trait loci,haplotype analysis and clustered regularly interspaced palindromic repeats(CRISPR)/CRISPR-associated protein9 methods.By revealing the new insights into the evolutionary patterns and biological roles of rice centromeres,our finding will facilitate future research on centromere biology and crop improvement.展开更多
基金supported by the National High-tech R&D Program of China(2009AA122003)
文摘Four wetland maps for all China have been produced,based on Landsat and CBERS-02B remote sensing data between 1978 and 2008 (1978,1990,2000 and 2008).These maps were mainly developed by manual interpretation and validated by substantial field investigation in 2009.Based on these maps,we analyzed the 2008 wetland distribution in China and discussed wetland changes and their drivers over the past 30 years.(i) There were about 324097 km 2 of wetlands in 2008,for which inland marshes or swamps were the most common wetland type (35%),with lakes (26%) second.Most of the wetlands were in Heilongjiang,Inner Mongolia,Qinghai and Tibet,occupying about 55% of the national wetland area.(ii) From 1978 to 2008,China's wetland area continually and significantly decreased,by about 33% based on changes in the wetland map.This was in sharp contrast to the increase in artificial wetlands,which increased by about 122%.Inland marshes accounted for the main loss of total wetlands from 1978 to 2000.From 2000 through 2008,riverine and lacustrine wetlands constituted the main wetland loss.Fortunately however,the rate of wetland loss decreased from 5523 to 831 km 2 /a.(iii) The change ratio of lost natural wetlands (including inland and coastal wetlands) to non-wetlands has decreased slightly over the past 30 years.From 1978 to 1990,nearly all natural wetlands (98%) lost were transformed into non-wetlands.However,the ratio declined to 86% from 1990 to 2000,and to 77% from 2000 to 2008.(iv) All Chinese provinces were divided into three groups according to patterns of wetland changes,which could relate to the driving forces of such changes.Tibet was completely different from other provinces,as it was one representative example in which there was a net wetland increase,because of global warming and decreased human activity since 1990.Increased economic development caused considerable wetland loss in most eastern provinces,and artificial wetlands increased.
基金supported by the National Natural Science Foundation of China(32188102,32101718)Guangdong Basic and Applied Basic Research Foundation(2023B1515020053)+1 种基金the Youth Innovation of Chinese Academy of Agricultural Sciences(Y20230C36)the specific research fund of The Innovation Platform for Academicians of Hainan Province(YSPTZX202303).
文摘Dear Editor,In 2005,the current commonly used rice reference genome(Oryza sativa ssp.japonica cv.Nipponbare)was initially released by the International Rice Genome Sequencing Project(International Rice Genome Sequencing Project,2005).Thereafter,the reference genome was further updated in 2013 with improved genome assembly(IRGSP-1.0)and gene annotations(MSU7,RAP-DB)(Kawahara et al.,2013;Sakai et al.,2013).In the past 10 years,this reference has been serving as one of the most important genetic resources for subsequent rice functional genomics efforts.As several rice genomes had been assembled into gapless chromosomes with only 2–5 telomeres absent(Li et al.,2021;Song et al.,2021;Zhang et al.,2022),the IRGSP1.0 and its annotations still performed as the most widely used reference.However,limitations of sequencing technology and intricate genomic organization led to an under-representation of complex regions in this reference,leaving a total of 72 major gaps(including 19 telomeres),167 minor gaps,and 779 unknown bases(Kawahara et al.,2013),with an estimated length of3%of the genome unsolved.
基金This work is supported by“the Fundamental Research Funds for the Central Universities”,111 project No.B20019Shanghai Natural Science Foundation,grant No.19ZR1466800.
文摘The Jiao Tong University Spectroscopic Telescope(JUST)is a 4.4-meter f/6.0 segmented-mirror telescope dedicated to spectroscopic observations.The JUST primary mirror is composed of 18 hexagonal segments,each with a diameter of 1.1 m.JUST provides two Nasmyth platforms for placing science instruments.One Nasmyth focus fits a field of view of 10′and the other has an extended field of view of 1.2°with correction optics.A tertiary mirror is used to switch between the two Nasmyth foci.JUST will be installed at a site at Lenghu in Qinghai Province,China,and will conduct spectroscopic observations with three types of instruments to explore the dark universe,trace the dynamic universe,and search for exoplanets:(1)a multi-fiber(2000 fibers)medium-resolution spectrometer(R=4000-5000)to spectroscopically map galaxies and large-scale structure;(2)an integral field unit(IFU)array of 500 optical fibers and/or a long-slit spectrograph dedicated to fast follow-ups of transient sources for multi-messenger astronomy;(3)a high-resolution spectrometer(R~100000)designed to identify Jupiter analogs and Earth-like planets,with the capability to characterize the atmospheres of hot exoplanets.
基金the National Natural Science Foundation of China(12090060,12090063,12105052,12005131,11905128,11925502)the Office of Science and Technology,Shanghai Municipal Government,China(22JC1410100)。
文摘Neutrinos from core-collapse supernovae are essential for understanding neutrino physics and stellar evolution.Dual-phase xenon dark matter detectors can be used to track explosions of galactic supernovae by detecting neutrinos through coherent elastic neutrino-nucleus scatterings.In this study,a variation of progenitor masses and explosion models are assumed to predict neutrino fluxes and spectra,which result in the number of expected neutrino events ranging from 6.6 to 13.7 at a distance of 10 kpc over a 10-s duration with negligible backgrounds at PandaX-4T.Two specialized triggering alarms for monitoring supernova burst neutrinos are built.The efficiency of detecting supernova explosions at various distances in the Milky Way is estimated.These alarms will be implemented in the real-time supernova monitoring system at PandaX-4T in the near future,which will provide supernova early warnings for the astronomical community.
基金supported by the National Natural Science Foundation of China(32188102,32372148)Innovation Program of Chinese Academy of Agricultural Sciences,the Youth Innovation of Chinese Academy of Agricultural Sciences(Y20230C36)+1 种基金Guangdong Basic and Applied Basic Research Foundation(2023B1515020053)the Youth Program of Guangdong Basic and Applied Research(2021A1515111123)。
文摘Rice(Oryza sativa)is a significant crop worldwide with a genome shaped by various evolutionary factors.Rice centromeres are crucial for chromosome segregation,and contain some unreported genes.Due to the diverse and complex centromere region,a comprehensive understanding of rice centromere structure and function at the population level is needed.We constructed a high-quality centromere map based on the rice super pangenome consisting of a 251-accession panel comprising both cultivated and wild species of Asian and African rice.We showed that rice centromeres have diverse satellite repeat CentO,which vary across chromosomes and subpopulations,reflecting their distinct evolutionary patterns.We also revealed that long terminal repeats(LTRs),especially young Gypsy-type LTRs,are abundant in the peripheral CentO-enriched regions and drive rice centromere expansion and evolution.Furthermore,high-quality genome assembly and complete telomere-to-telomere(T2T)reference genome enable us to obtain more centromeric genome information despite mapping and cloning of centromere genes being challenging.We investigated the association between structural variations and gene expression in the rice centromere.A centromere gene,OsMAB,which positively regulates rice tiller number,was further confirmed by expression quantitative trait loci,haplotype analysis and clustered regularly interspaced palindromic repeats(CRISPR)/CRISPR-associated protein9 methods.By revealing the new insights into the evolutionary patterns and biological roles of rice centromeres,our finding will facilitate future research on centromere biology and crop improvement.
