The characteristics of haze days and the climatic background are analyzed by using daily observations of haze,precipitation,mean and maximum wind speed of 664 meteorological stations for the period of 1961–2012.The r...The characteristics of haze days and the climatic background are analyzed by using daily observations of haze,precipitation,mean and maximum wind speed of 664 meteorological stations for the period of 1961–2012.The results show that haze days occur significantly more often in eastern China than in western China.The annual number of haze days is 5–30 d in most parts of central-eastern China,with some areas experiencing more than 30 d,while less than 5 d are averagely occurring in western China.Haze days are mainly concentrated in the winter half-year,with most in winter,followed by autumn,spring,and then summer.Nearly 20%of annual haze days are experienced in December.The haze days in central-eastern China in the winter half-year have a significant increasing trend of 1.7 d per decade during 1961–2012.There were great increases in haze days in the 1960s,1970s and the beginning of the 21st century.There was also significant abrupt changes of haze days in the early 1970s and 2000s.From 1961 to 2012,haze days in the winter half-year increased in South China,the middle-lower reaches of the Yangtze River,and North China,but decreased in Northeast China,eastern Northwest China and eastern Southwest China.The number of persistent haze is rising.The Longer the haze,the greater the proportion to the number persistent haze.Certain climatic conditions exacerbated the occurrence of haze.The correlation coefficient between haze days and precipitation days in the winter half-year is mainly negative in central-eastern China.The precipitation days show a decreasing trend in most parts of China,with a rate of around–4.0 d per decade in central-eastern China,which reduces the sedimentation capacity of atmospheric pollutants.During the period of 1961–2012,the correlation coefficients between haze days and mean wind speed and strong wind days are mainly negative in central-eastern China,while there exists positive correlation between haze days and breeze days in the winter half-year.The mean wind speed and strong wind days are decreasing,while breeze days are increasing in most parts of China,which is benefitial to the reduction of the pollutants diffusion capacity.As a result,haze occurs more easily.展开更多
Phenological background information for alpine species is limited from extremely high altitudes. Flowering and fruiting phenology was monitored for 24 plant species at 5,180 m a.s.1, near the base camp area on the nor...Phenological background information for alpine species is limited from extremely high altitudes. Flowering and fruiting phenology was monitored for 24 plant species at 5,180 m a.s.1, near the base camp area on the north slope of Mt. Qomolangma （Mt. Everest） in Tibet, western China. The dates of first flowering, peak flowering, end of flowering, first fruiting, peak fruiting and flowering period were recorded. There was a wide variation in onset of flowering, long flowering duration, a relative synchrony between the onset of flowering and fruiting, and one species was exclusively vegetative. These results suggest that the species have evolved various phenological strategies as adaptations to the short growing season with limited resources and pollinators in this harsh alpine environment at extremely high elevations. With a background of global warming, local plant species will represent an advancing trend in onset of flowering.展开更多
The latest sharp uplift of the Tibetan Plateau and adjacent mountains occurred at the end of the early Pleistocene. The uplift of the Plateau resulted from Late Mesozoic--Cenozoic compressional structure due to the su...The latest sharp uplift of the Tibetan Plateau and adjacent mountains occurred at the end of the early Pleistocene. The uplift of the Plateau resulted from Late Mesozoic--Cenozoic compressional structure due to the subduction of the Indian Plate beneath the Asian continent. This event definitively effected the formation of basin-mountain relief, Cenozoic basin deformation, large scale aridity and desertification of western China. The Australasian meteorites impact event happened ca. 0.8 Ma ago, located in the triangle area of the Indian Ocean ridge (20°S/67°E). The impact may have resulted in an acceleration of speeding of the Indian Ocean ridge pushing the Indian Plate to subduct rapidly northward. Thus, the impact event can give reasonable explanation for the dynamic background of the latest rapid uplift of the Tibetan Plateau and the continental deformation of western China and even of the Middle Asia.展开更多
Selenocosmia huwena and Selenocosmia hainana are two tarantula species found in southern China.Their venoms contain abundant peptide toxins.Two new neurotoxic peptides,huwentoxin-Ⅲ(HWTX-Ⅲ) and hainantoxin-VI(HNTX-VI...Selenocosmia huwena and Selenocosmia hainana are two tarantula species found in southern China.Their venoms contain abundant peptide toxins.Two new neurotoxic peptides,huwentoxin-Ⅲ(HWTX-Ⅲ) and hainantoxin-VI(HNTX-VI),were obtained from the venom using ion-exchange chromatography and reverse-phase high performance liquid chromatography(RP-HPLC).The mechanism of action of HWTX-Ⅲ and HNTX-VI on insect neuronal voltage-gated sodium channels(VGSCs) was studied via whole-cell patch clamp techniques.In a fashion similar to δ-atracotoxins,HNTX-VI can induce a slowdown of current inactivation of the VGSC and reduction in the peak of Na+ current in cockroach dorsal unpaired median(DUM) neurons.Meanwhile,10 μmol/L HNTX-IV caused a positive shift of steady-state inactivation of sodium channel.HWTX-ⅡI inhibited VGSCs on DUM neurons(concentration of toxin at half-maximal inhibition(IC50)≈1.106 μmol/L) in a way much similar to tetrodotoxin(TTX).HWTX-Ⅲ had no effect on the kinetics of activation and inactivation.The shift in the steady-state inactivation curve was distinct from other depressant spider toxins.The diverse effect and the mechanism of action of the two insect toxins illustrate the diverse biological activities of spider toxins and provide a fresh theoretical foundation to design and develop novel insecticides.展开更多
基金supported by the National Basic Research Program of China(No.2012CB955902)
文摘The characteristics of haze days and the climatic background are analyzed by using daily observations of haze,precipitation,mean and maximum wind speed of 664 meteorological stations for the period of 1961–2012.The results show that haze days occur significantly more often in eastern China than in western China.The annual number of haze days is 5–30 d in most parts of central-eastern China,with some areas experiencing more than 30 d,while less than 5 d are averagely occurring in western China.Haze days are mainly concentrated in the winter half-year,with most in winter,followed by autumn,spring,and then summer.Nearly 20%of annual haze days are experienced in December.The haze days in central-eastern China in the winter half-year have a significant increasing trend of 1.7 d per decade during 1961–2012.There were great increases in haze days in the 1960s,1970s and the beginning of the 21st century.There was also significant abrupt changes of haze days in the early 1970s and 2000s.From 1961 to 2012,haze days in the winter half-year increased in South China,the middle-lower reaches of the Yangtze River,and North China,but decreased in Northeast China,eastern Northwest China and eastern Southwest China.The number of persistent haze is rising.The Longer the haze,the greater the proportion to the number persistent haze.Certain climatic conditions exacerbated the occurrence of haze.The correlation coefficient between haze days and precipitation days in the winter half-year is mainly negative in central-eastern China.The precipitation days show a decreasing trend in most parts of China,with a rate of around–4.0 d per decade in central-eastern China,which reduces the sedimentation capacity of atmospheric pollutants.During the period of 1961–2012,the correlation coefficients between haze days and mean wind speed and strong wind days are mainly negative in central-eastern China,while there exists positive correlation between haze days and breeze days in the winter half-year.The mean wind speed and strong wind days are decreasing,while breeze days are increasing in most parts of China,which is benefitial to the reduction of the pollutants diffusion capacity.As a result,haze occurs more easily.
基金supported jointly by 111 Project (Grant No. B08037)Project 6 of the National Basic Research Program of China (Grant No. 2005CB422006)a Natural Sciences and Engineering Research Council (Canada) discovery grant to RT
文摘Phenological background information for alpine species is limited from extremely high altitudes. Flowering and fruiting phenology was monitored for 24 plant species at 5,180 m a.s.1, near the base camp area on the north slope of Mt. Qomolangma （Mt. Everest） in Tibet, western China. The dates of first flowering, peak flowering, end of flowering, first fruiting, peak fruiting and flowering period were recorded. There was a wide variation in onset of flowering, long flowering duration, a relative synchrony between the onset of flowering and fruiting, and one species was exclusively vegetative. These results suggest that the species have evolved various phenological strategies as adaptations to the short growing season with limited resources and pollinators in this harsh alpine environment at extremely high elevations. With a background of global warming, local plant species will represent an advancing trend in onset of flowering.
基金Supported by Projects of NSFC (Nos. 40872127, 40572135)
文摘The latest sharp uplift of the Tibetan Plateau and adjacent mountains occurred at the end of the early Pleistocene. The uplift of the Plateau resulted from Late Mesozoic--Cenozoic compressional structure due to the subduction of the Indian Plate beneath the Asian continent. This event definitively effected the formation of basin-mountain relief, Cenozoic basin deformation, large scale aridity and desertification of western China. The Australasian meteorites impact event happened ca. 0.8 Ma ago, located in the triangle area of the Indian Ocean ridge (20°S/67°E). The impact may have resulted in an acceleration of speeding of the Indian Ocean ridge pushing the Indian Plate to subduct rapidly northward. Thus, the impact event can give reasonable explanation for the dynamic background of the latest rapid uplift of the Tibetan Plateau and the continental deformation of western China and even of the Middle Asia.
基金supported by the National Natural Science Foundation of China (No.30500146)the National Basic Research Program (973) of China (No.2006CB708508)
文摘Selenocosmia huwena and Selenocosmia hainana are two tarantula species found in southern China.Their venoms contain abundant peptide toxins.Two new neurotoxic peptides,huwentoxin-Ⅲ(HWTX-Ⅲ) and hainantoxin-VI(HNTX-VI),were obtained from the venom using ion-exchange chromatography and reverse-phase high performance liquid chromatography(RP-HPLC).The mechanism of action of HWTX-Ⅲ and HNTX-VI on insect neuronal voltage-gated sodium channels(VGSCs) was studied via whole-cell patch clamp techniques.In a fashion similar to δ-atracotoxins,HNTX-VI can induce a slowdown of current inactivation of the VGSC and reduction in the peak of Na+ current in cockroach dorsal unpaired median(DUM) neurons.Meanwhile,10 μmol/L HNTX-IV caused a positive shift of steady-state inactivation of sodium channel.HWTX-ⅡI inhibited VGSCs on DUM neurons(concentration of toxin at half-maximal inhibition(IC50)≈1.106 μmol/L) in a way much similar to tetrodotoxin(TTX).HWTX-Ⅲ had no effect on the kinetics of activation and inactivation.The shift in the steady-state inactivation curve was distinct from other depressant spider toxins.The diverse effect and the mechanism of action of the two insect toxins illustrate the diverse biological activities of spider toxins and provide a fresh theoretical foundation to design and develop novel insecticides.
