以天然云冷杉(Picea jezoensis var.microsperma(Lindl.)W.C.Cheng&L.K.Fu and Abiesnephrolepis(Trautv.)Maxim.)针阔混交林为研究对象,基于4块1hm^2固定样地林分调查数据和等距离网格布点取样的400个半分解层凋落物样品的养分测...以天然云冷杉(Picea jezoensis var.microsperma(Lindl.)W.C.Cheng&L.K.Fu and Abiesnephrolepis(Trautv.)Maxim.)针阔混交林为研究对象,基于4块1hm^2固定样地林分调查数据和等距离网格布点取样的400个半分解层凋落物样品的养分测定数据,采用地统计学方法,分析凋落物磷浓度、归还量及利用效率的空间格局特征及其影响因素.结果表明:4块样地凋落物磷浓度均值为1.26g/kg,归还量均值为24.57kg/hm^2,利用效率均值为841.74,均表现为中等强度变异,具有明显的空间异质性,且同一样地,变异程度呈现出磷归还量>磷利用效率>磷浓度.凋落物磷浓度、归还量(样地Ⅲ和Ⅳ结构比大于75%,其空间异质性主要由随机效应引起,不适合进行空间插值)和利用效率主要受结构性因素影响,具有较高的空间自相关性.同一样地磷利用效率的空间异质性较磷浓度及归还量低,各样地磷浓度、归还量和利用效率空间自相关范围分别为9.9-40.5m、11.9-52.9m和8.1-39.3m.同一样地磷利用效率的分形维数高于磷浓度,空间格局较磷浓度复杂,磷浓度空间依赖性更强,具有更好的结构性.凋落物磷浓度、归还量(除样地Ⅲ和Ⅳ)和利用效率呈现条带状和斑块状梯度性分布,且磷浓度和利用效率的空间分布格局相似.凋落物磷浓度、归还量和利用效率受到郁闭度、物种数和植物多样性等多种因子的影响.展开更多
Scutellaria baicalensis(S.baicalensis)and Scutellaria barbata(S.barbata)are common medicinal plants of the Lamiaceae family.Both produce specific flavonoid compounds,including baicalein,scutellarein,norwogonin,and wog...Scutellaria baicalensis(S.baicalensis)and Scutellaria barbata(S.barbata)are common medicinal plants of the Lamiaceae family.Both produce specific flavonoid compounds,including baicalein,scutellarein,norwogonin,and wogonin,as well as their glycosides,which exhibit antioxidant and antitumor activities.Here,we report chromosome-level genome assemblies of S.baicalensis and S.barbata with quantitative chromosomal variation(2 n=18 and 2 n=26,respectively).The divergence of S.baicalensis and S.barbata occurred far earlier than previously reported,and a whole-genome duplication(WGD)event was identified.The insertion of long terminal repeat elements after speciation might be responsible for the observed chromosomal expansion and rearrangement.Comparative genome analysis of the congeneric species revealed the species-specific evolution of chrysin and apigenin biosynthetic genes,such as the S.baicalensis-specific tandem duplication of genes encoding phenylalanine ammonia lyase and chalcone synthase,and the S.barbata-specific duplication of genes encoding 4-Co A ligase.In addition,the paralogous duplication,colinearity,and expression diversity of CYP82 D subfamily members revealed the functional divergence of genes encoding flavone hydroxylase between S.baicalensis and S.barbata.Analyzing these Scutellaria genomes reveals the common and species-specific evolution of flavone biosynthetic genes.Thus,these findings would facilitate the development of molecular breeding and studies of biosynthesis and regulation of bioactive compounds.展开更多
目的评价鼻呼出气一氧化氮(nasal nitric oxide,nNO)在鉴别慢性鼻-鼻窦炎不伴鼻息肉(chronicrhinosinusitis without nasal polyps,CRSsNP)和慢性鼻-鼻窦炎伴鼻息肉(chronic rhinosinusitis with nasal polyps,CRSwNP)诊断中的临床应用...目的评价鼻呼出气一氧化氮(nasal nitric oxide,nNO)在鉴别慢性鼻-鼻窦炎不伴鼻息肉(chronicrhinosinusitis without nasal polyps,CRSsNP)和慢性鼻-鼻窦炎伴鼻息肉(chronic rhinosinusitis with nasal polyps,CRSwNP)诊断中的临床应用及其与鼻窦CT的相关关系。方法本研究收集连续88例慢性鼻-鼻窦炎(CRS)患者和20名健康志愿者。使用NIOX设备测量呼出的nNO水平。鼻内镜检查和鼻窦计算机断层扫描评估受试者的鼻腔及鼻窦炎症状态,皮肤点刺试验用于确认特应性状态。结果CRSsNP患者的nNO水平高于CRSwNP患者[(591±153)ppbvs(360±181)ppb,P<0.001],而CRS患者的nNO水平低于对照组[(449±204)ppbvs(881±161)ppb,P<0.001].在特应性和非特应性CRS患者中,nNO水平与Lund-Mackay评分呈负相关(r=-0.45,P=0.016;r=-0.600,P<0.001).与特应性患者相比,伴或不伴鼻息肉的非特应性患者表现出较低的nNO水平[非特应性CRSsNPvs特应性CRSsNP,(503±92)ppbvs(734±120)ppb,P<0.001;非特应性CRSwNPvs特异性CRSwNP,(299±150)ppbvs(518±161)ppb,P<0.001].接受者操作特征(ROC)曲线分析CRSwNP、CRSsNP和健康对照以及特应性和非特应性亚组中的患者,具有可接受的敏感性和特异性(超过70%-90%).结论nNO水平可用于区分CRSwNP和CRSsNP,且和鼻窦CT评分呈负相关。然而,作为CRS的诊断或监测生物标志物,nNO受患者特应性状态的影响。展开更多
The Tibetan Plateau(TP) is a key area affecting forecasts of weather and climate in China and occurrences of extreme weather and climate events over the world. The China Meteorological Administration, the National Nat...The Tibetan Plateau(TP) is a key area affecting forecasts of weather and climate in China and occurrences of extreme weather and climate events over the world. The China Meteorological Administration, the National Natural Science Foundation of China, and the Chinese Academy of Sciences jointly initiated the Third Tibetan Plateau Atmospheric Science Experiment(TIPEX-Ⅲ) in 2013, with an 8–10-yr implementation plan. Since its preliminary field measurements conducted in 2013, routine automatic sounding systems have been deployed at Shiquanhe, Gaize, and Shenzha stations in western TP, where no routine sounding observations were available previously. The observational networks for soil temperature and soil moisture in the central and western TP have also been established. Meanwhile, the plateau-scale and regional-scale boundary layer observations, cloud–precipitation microphysical observations with multiple radars and aircraft campaigns, and tropospheric–stratospheric air composition observations at multiple sites, were performed. The results so far show that the turbulent heat exchange coefficient and sensible heat flux are remarkably lower than the earlier estimations at grassland, meadow, and bare soil surfaces of the central and western TP. Climatologically, cumulus clouds over the main body of the TP might develop locally instead of originating from the cumulus clouds that propagate northward from South Asia. The TIPEX-Ⅲ observations up to now also reveal diurnal variations, macro-and microphysical characteristics, and water-phase transition mechanisms, of cumulus clouds at Naqu station. Moreover, TIPEX-Ⅲ related studies have proposed a maintenance mechanism responsible for the Asian "atmospheric water tower" and demonstrated the effects of the TP heating anomalies on African, Asian, and North American climates. Additionally, numerical modeling studies show that the Γ distribution of raindrop size is more suitable for depicting the TP raindrop characteristics compared to the M–P distribution, the o展开更多
The Panda X-4T experiment, a 4-ton scale dark matter direct detection experiment, is being planned at the China Jinping Underground Laboratory. In this paper we present a simulation study of the expected background in...The Panda X-4T experiment, a 4-ton scale dark matter direct detection experiment, is being planned at the China Jinping Underground Laboratory. In this paper we present a simulation study of the expected background in this experiment. In a 2.8-ton fiducial mass and the signal region between 1-10 keV electron equivalent energy, the total electron recoil background is found to be 4.9 × 10^(-5) kg^(-1) d^(-1) keV^(-1). The nuclear recoil background in the same region is 2.8 × 10^(-7) kg^(-1) d^(-1) keV^(-1). With an exposure of 5.6 ton-years, the sensitivity of Panda X-4 T could reach a minimum spin-independent dark matter-nucleon cross section of 6 × 10^(-48) cm^2 at a dark matter mass of 40 Ge V/c^2.展开更多
We analyzed vertical distributions of ozone (O3) in the lower troposphere (< 5 km above ground) at Lin’an (119.75°E, 30.30°N), Zhejiang Province using electrochemical concen- tration cell (ECC) ozonesond...We analyzed vertical distributions of ozone (O3) in the lower troposphere (< 5 km above ground) at Lin’an (119.75°E, 30.30°N), Zhejiang Province using electrochemical concen- tration cell (ECC) ozonesonde data obtained from February 21 to April 13, 2001. The results showed that the vertical O3 distributions are controlled by metrological conditions and the char- acteristics of O3 profiles are related to those of wet bulb potential temperature and wind field. O3 below 2 km showed that the strongest variability and enhanced O3 mixing ratios were associated with easterly winds that blow pollutants from the upwind source region of the Yangtze River Delta (YRD) region. Vertical O3 profiles below 5 km can be grouped into 5 categories: (1) peak mixing ratio type, (2) well-mixed type, (3) layered-structure type, (4) episodic pollution type and (5) alti- tudinal increasing type. Vertical distributions of O3 affected by regional transport of polluted air masses were investigated. Transport of polluted air from high latitudes of northern China, ac- companying subsiding motion of air and stagnant atmospheric conditions are important factors that lead to high mixing ratios of O3 at Lin’an. The stagnant atmospheric conditions associated with a continental high pressure system and pollution plume transported from the YRD and cen- tral-eastern China also lead to regional accumulation of O3 and high O3 mixing ratio at Lin’an. Long-range transport of O3 and pollutants from the Pearl River Delta in South China and in-situ O3 formation also resulted in elevated O3 mixing ratios at around 1 km altitudes and layered O3 distribution in the lower troposphere.展开更多
文摘以天然云冷杉(Picea jezoensis var.microsperma(Lindl.)W.C.Cheng&L.K.Fu and Abiesnephrolepis(Trautv.)Maxim.)针阔混交林为研究对象,基于4块1hm^2固定样地林分调查数据和等距离网格布点取样的400个半分解层凋落物样品的养分测定数据,采用地统计学方法,分析凋落物磷浓度、归还量及利用效率的空间格局特征及其影响因素.结果表明:4块样地凋落物磷浓度均值为1.26g/kg,归还量均值为24.57kg/hm^2,利用效率均值为841.74,均表现为中等强度变异,具有明显的空间异质性,且同一样地,变异程度呈现出磷归还量>磷利用效率>磷浓度.凋落物磷浓度、归还量(样地Ⅲ和Ⅳ结构比大于75%,其空间异质性主要由随机效应引起,不适合进行空间插值)和利用效率主要受结构性因素影响,具有较高的空间自相关性.同一样地磷利用效率的空间异质性较磷浓度及归还量低,各样地磷浓度、归还量和利用效率空间自相关范围分别为9.9-40.5m、11.9-52.9m和8.1-39.3m.同一样地磷利用效率的分形维数高于磷浓度,空间格局较磷浓度复杂,磷浓度空间依赖性更强,具有更好的结构性.凋落物磷浓度、归还量(除样地Ⅲ和Ⅳ)和利用效率呈现条带状和斑块状梯度性分布,且磷浓度和利用效率的空间分布格局相似.凋落物磷浓度、归还量和利用效率受到郁闭度、物种数和植物多样性等多种因子的影响.
基金the National Key R&D Program of China(Grant No.2019YFC1711100)the National Natural Science Foundation of China(Grant No.31700264)the Chinese Academy of Medical Sciences(CAMS)Innovation Fund for Medical Sciences(CIFMS)(Grant No.2016-I2M3-016)。
文摘Scutellaria baicalensis(S.baicalensis)and Scutellaria barbata(S.barbata)are common medicinal plants of the Lamiaceae family.Both produce specific flavonoid compounds,including baicalein,scutellarein,norwogonin,and wogonin,as well as their glycosides,which exhibit antioxidant and antitumor activities.Here,we report chromosome-level genome assemblies of S.baicalensis and S.barbata with quantitative chromosomal variation(2 n=18 and 2 n=26,respectively).The divergence of S.baicalensis and S.barbata occurred far earlier than previously reported,and a whole-genome duplication(WGD)event was identified.The insertion of long terminal repeat elements after speciation might be responsible for the observed chromosomal expansion and rearrangement.Comparative genome analysis of the congeneric species revealed the species-specific evolution of chrysin and apigenin biosynthetic genes,such as the S.baicalensis-specific tandem duplication of genes encoding phenylalanine ammonia lyase and chalcone synthase,and the S.barbata-specific duplication of genes encoding 4-Co A ligase.In addition,the paralogous duplication,colinearity,and expression diversity of CYP82 D subfamily members revealed the functional divergence of genes encoding flavone hydroxylase between S.baicalensis and S.barbata.Analyzing these Scutellaria genomes reveals the common and species-specific evolution of flavone biosynthetic genes.Thus,these findings would facilitate the development of molecular breeding and studies of biosynthesis and regulation of bioactive compounds.
文摘目的评价鼻呼出气一氧化氮(nasal nitric oxide,nNO)在鉴别慢性鼻-鼻窦炎不伴鼻息肉(chronicrhinosinusitis without nasal polyps,CRSsNP)和慢性鼻-鼻窦炎伴鼻息肉(chronic rhinosinusitis with nasal polyps,CRSwNP)诊断中的临床应用及其与鼻窦CT的相关关系。方法本研究收集连续88例慢性鼻-鼻窦炎(CRS)患者和20名健康志愿者。使用NIOX设备测量呼出的nNO水平。鼻内镜检查和鼻窦计算机断层扫描评估受试者的鼻腔及鼻窦炎症状态,皮肤点刺试验用于确认特应性状态。结果CRSsNP患者的nNO水平高于CRSwNP患者[(591±153)ppbvs(360±181)ppb,P<0.001],而CRS患者的nNO水平低于对照组[(449±204)ppbvs(881±161)ppb,P<0.001].在特应性和非特应性CRS患者中,nNO水平与Lund-Mackay评分呈负相关(r=-0.45,P=0.016;r=-0.600,P<0.001).与特应性患者相比,伴或不伴鼻息肉的非特应性患者表现出较低的nNO水平[非特应性CRSsNPvs特应性CRSsNP,(503±92)ppbvs(734±120)ppb,P<0.001;非特应性CRSwNPvs特异性CRSwNP,(299±150)ppbvs(518±161)ppb,P<0.001].接受者操作特征(ROC)曲线分析CRSwNP、CRSsNP和健康对照以及特应性和非特应性亚组中的患者,具有可接受的敏感性和特异性(超过70%-90%).结论nNO水平可用于区分CRSwNP和CRSsNP,且和鼻窦CT评分呈负相关。然而,作为CRS的诊断或监测生物标志物,nNO受患者特应性状态的影响。
基金Supported by the China Meteorological Administration Special Public Welfare Research Fund for The Third Tibetan Plateau Atmospheric Science Experiment(TIPEX-Ⅲ)—Boundary Layer and Tropospheric Observations(GYHY201406001)
文摘The Tibetan Plateau(TP) is a key area affecting forecasts of weather and climate in China and occurrences of extreme weather and climate events over the world. The China Meteorological Administration, the National Natural Science Foundation of China, and the Chinese Academy of Sciences jointly initiated the Third Tibetan Plateau Atmospheric Science Experiment(TIPEX-Ⅲ) in 2013, with an 8–10-yr implementation plan. Since its preliminary field measurements conducted in 2013, routine automatic sounding systems have been deployed at Shiquanhe, Gaize, and Shenzha stations in western TP, where no routine sounding observations were available previously. The observational networks for soil temperature and soil moisture in the central and western TP have also been established. Meanwhile, the plateau-scale and regional-scale boundary layer observations, cloud–precipitation microphysical observations with multiple radars and aircraft campaigns, and tropospheric–stratospheric air composition observations at multiple sites, were performed. The results so far show that the turbulent heat exchange coefficient and sensible heat flux are remarkably lower than the earlier estimations at grassland, meadow, and bare soil surfaces of the central and western TP. Climatologically, cumulus clouds over the main body of the TP might develop locally instead of originating from the cumulus clouds that propagate northward from South Asia. The TIPEX-Ⅲ observations up to now also reveal diurnal variations, macro-and microphysical characteristics, and water-phase transition mechanisms, of cumulus clouds at Naqu station. Moreover, TIPEX-Ⅲ related studies have proposed a maintenance mechanism responsible for the Asian "atmospheric water tower" and demonstrated the effects of the TP heating anomalies on African, Asian, and North American climates. Additionally, numerical modeling studies show that the Γ distribution of raindrop size is more suitable for depicting the TP raindrop characteristics compared to the M–P distribution, the o
基金supported by a 985-Ⅲ grant from Shanghai Jiao Tong University,the National Natural Science Foundation of China(Grant Nos.11435008,11455001,11505112,11525522,11775141,and 11755001)the Ministry of Science and Technology of China(Grant No.2016YFA0400301)+2 种基金the Office of Science and Technology,Shanghai Municipal Government(Grant Nos.11DZ2260700,and 16DZ2260200)the Key Laboratory for Particle Physics,Astrophysics and Cosmology,Ministry of Educationsupported in part by the Chinese Academy of Sciences Center for Excellence in Particle Physics(CCEPP)and Hongwen Foundation in Hong Kong
文摘The Panda X-4T experiment, a 4-ton scale dark matter direct detection experiment, is being planned at the China Jinping Underground Laboratory. In this paper we present a simulation study of the expected background in this experiment. In a 2.8-ton fiducial mass and the signal region between 1-10 keV electron equivalent energy, the total electron recoil background is found to be 4.9 × 10^(-5) kg^(-1) d^(-1) keV^(-1). The nuclear recoil background in the same region is 2.8 × 10^(-7) kg^(-1) d^(-1) keV^(-1). With an exposure of 5.6 ton-years, the sensitivity of Panda X-4 T could reach a minimum spin-independent dark matter-nucleon cross section of 6 × 10^(-48) cm^2 at a dark matter mass of 40 Ge V/c^2.
基金supported by the Research Grant Council of Hong Kong(PolyU.5061/99E and PolyU.5048/02E)an institutional research grant of Hong Kong Polytechnic University(ASD 502)partly by the National Natural Science Foundation of China(Grant No.49975026).
文摘We analyzed vertical distributions of ozone (O3) in the lower troposphere (< 5 km above ground) at Lin’an (119.75°E, 30.30°N), Zhejiang Province using electrochemical concen- tration cell (ECC) ozonesonde data obtained from February 21 to April 13, 2001. The results showed that the vertical O3 distributions are controlled by metrological conditions and the char- acteristics of O3 profiles are related to those of wet bulb potential temperature and wind field. O3 below 2 km showed that the strongest variability and enhanced O3 mixing ratios were associated with easterly winds that blow pollutants from the upwind source region of the Yangtze River Delta (YRD) region. Vertical O3 profiles below 5 km can be grouped into 5 categories: (1) peak mixing ratio type, (2) well-mixed type, (3) layered-structure type, (4) episodic pollution type and (5) alti- tudinal increasing type. Vertical distributions of O3 affected by regional transport of polluted air masses were investigated. Transport of polluted air from high latitudes of northern China, ac- companying subsiding motion of air and stagnant atmospheric conditions are important factors that lead to high mixing ratios of O3 at Lin’an. The stagnant atmospheric conditions associated with a continental high pressure system and pollution plume transported from the YRD and cen- tral-eastern China also lead to regional accumulation of O3 and high O3 mixing ratio at Lin’an. Long-range transport of O3 and pollutants from the Pearl River Delta in South China and in-situ O3 formation also resulted in elevated O3 mixing ratios at around 1 km altitudes and layered O3 distribution in the lower troposphere.
