The Walker circulation is one of the major components of the large-scale tropical atmospheric circulation and variations in its strength are critical to equatorial Pacific Ocean circulation. It has been argued in the ...The Walker circulation is one of the major components of the large-scale tropical atmospheric circulation and variations in its strength are critical to equatorial Pacific Ocean circulation. It has been argued in the literature that during the 20th century the Walker circulation weakened, and that this weakening was attributable to anthropogenic climate change. By using updated observations, we show that there has been a rapid interdecadal enhancement of the Walker circulation since the late 1990s. Associated with this enhancement is enhanced precipitation in the tropical western Pacific, anomalous westerlies in the upper troposphere, descent in the central and eastern tropical Pacific, and anomalous surface easterlies in the western and central tropical Pacific. The characteristics of associated oceanic changes are a strengthened thermocline slope and an enhanced zonal SST gradient across the tropical Pacific. Many characteristics of these changes are similar to those associated with the mid-1970s climate shift with an opposite sign. We also show that the interdecadal variability of the Walker circulation in the tropical Pacific is inversely correlated to the interdecadal variability of the zonal circulation in the tropical Atlantic. An enhancement of the Walker circulation in the tropical Pacific is associated with a weakening zonal circulation in the tropical Atlantic and vise versa, implying an inter-Atlantic-Pacific connection of the zonal overturning circulation variation. Whether these recent changes will be sustained is not yet clear, but our research highlights the importance of understanding the interdecadal variability, as well as the long-term trends, that influence tropical circulation.展开更多
The goal of this research is to describe and analyze women’s wear in the late Qing Dynasty andearly Republic Period(late 19th c.—early 20th c.),with an emphasis on the daily informal orsemi-formal wear,though some f...The goal of this research is to describe and analyze women’s wear in the late Qing Dynasty andearly Republic Period(late 19th c.—early 20th c.),with an emphasis on the daily informal orsemi-formal wear,though some formal or ceremonial costumes such as wedding dress will also beincluded.This study will use Chinese costumes and textiles from many museums to fill in theblanks left by previous research and to give a more detailed and accurate description.It will alsouse historical documents to find the original names of these items and to illustrate a general conceptof their usage on different occasions.The different categories of women’s wear will be described in the following order:①robes orcoats;②jackets;③waistcoats or vests;④skirts;⑤pants and leggings;⑥shoes and socks;⑦headdresses;and⑧others.Of every category,the textiles,decoration,cut,form,style,colourand motif will be discussed.The way in which these items were combined will also be discussed.The comparison between women’s wear and men’s wear,women’s and children’s informal andformal dress will be given.Here are some tentative conclusions.First,the Manchu and Han style coexisted and mixedwith each other and were worn by both Manchu and Han women.Second,the basic silhouettesand cuts were relatively stable and conventional,while the decorations and details(openings,fasten-ings,pleats,vents,collars and hemlines)were different.The former represented accepted socialstandards while the latter could be a matter of personal taste.Third,women’s wear in that periodwere highly stylized,miscellaneous,elaborate,detailed,multicolored and multi-thematic.展开更多
Extensive organic-matter （OM） rich facies （black shales） occur in the Ordo-Silurian boundary successions in the Yangtze area, South China. To investigate the redox changes of the Yangtze Sea during the Ordo-Siluri...Extensive organic-matter （OM） rich facies （black shales） occur in the Ordo-Silurian boundary successions in the Yangtze area, South China. To investigate the redox changes of the Yangtze Sea during the Ordo-Silurian transition, two OM sections （Wangjiawan in Yichang, Hubei Province, and Sanjiaguan in Zhangjiajie, Hunan Province） straddling the Ordo-Silurian boundary are studied. The measurements finished in this study include contents of the total organic carbon （TOC）, pyrite sulphur, and different species of Fe, including dithionite-extractable Fe （FED）, pyrite Fe （FeP）, HCl-extractable Fe （FeH）, and total Fe （FeT）, in black shales, as well as other redox proxies, such as the SIC ratio, the ratio between highly reactive Fe （FeHR = FeD ＋ FeP） and FeT, and the FeP/（FeP ＋ FeH） ratio, known as the degree of pyritization （DOP）. In the Wangjiawan section, the Middle Ashgill sediments have high FeHR/FeT ratios （0.20-0.77; avg. 0.45）, high DOP values （0.21-0.72; avg. 0.54）, and a relatively constant sulfur content independent of the organic carbon content. By the contrast, the mid-early Hirnantian deposits generally have low FeHR/FeT ratios （0.10-0.35; avg. 0.21）, low DOP values （0.11- 0.40; avg. 0.28）, and SIC values are clustering on the normal marine value （SIC = 0.36）. The late Hirnantian and early Rhuddanian deposits, similar to those of the Middle Ashgill deposits, are characterized by high FeHR/FeT ratios （0.32-0.49; avg. 0.41）, high DOP values （0.46-0.68; avg. 0.53） and fairly constant sulfur contents. These data suggest the occurrences of marine anoxia on the Yangtze Sea shelf during intervals of the Mid Ashgill, Late Hirnantian and Early Rhuddanian, and ventilated and oxygenated marine conditions during the mid-early Hirnantian time. The mid-early Hirnantian ventilated event was concomitant with the global glacial period, likely resulted from the glacio-eustatic sea-level fall and subsequent circulation of cold, dense oxygenated waters upon the shelf seabed. Accordingly, the abrupt change from oxygenated to anoxic marine waters from the late Hirnantian and the early Rhuddanian were resulted from the post-glacial rise of eustatic sea level. Combined with the data from Sanjiaguan section near the subemergent highland, salinity stratification of water columns are strongly evidenced by very low S/C ratios （ 0.00-0.08, avg. 0.02）, low FeHR/FeT ratios （0.10-0.37, avg. 0.27）, low DOP values （0.01-0.27, avg. 0.10）, and TOC contents （0.72%-4.27%, avg. 2.55%）. Under this circumstance, the anoxic water columns could have formed beneath the halocline, above which desalinized waters formed. In the Wangjiawan section, TOC contents are generally high （0.94- 9.32%, avg. 4.44%）, but low （0.35%-2.12%, avg. 1.29%） in the mid-early Hirnantian that is coincident with the oceanic oxic stage, together with relation of the organic contents to the stratal thickness, suggesting that the accumulation of the organic matter was mainly controlled by the oxygen levels of the water columns; on the other hand, productivity and depositional rate may also have played a role in the organic accumulation and preservation.展开更多
Based on monthly mean temperature and precipitation, the changing processes and tendencies of temperature and precipitation in Qinghai-Xizang Plateau from 1950s to the early 1990s are analysed. The change of temperatu...Based on monthly mean temperature and precipitation, the changing processes and tendencies of temperature and precipitation in Qinghai-Xizang Plateau from 1950s to the early 1990s are analysed. The change of temperature in the past 40 a is almost unanimous on the spatial scale. The first area becoming warmer is the southeastern Tibet. The plateau is divided into 5 parts according to the change of temperature, and 9 parts according to the change of precipitation. For the past 40a some area has been warmer and drier, others warmer and wetter.展开更多
Brain structure and cognitive function change in the temporal lobe, hippocampus, and prefrontal cortex of patients with mild cognitive impairment and Alzheimer＇s disease, and brain network-connection strength, networ...Brain structure and cognitive function change in the temporal lobe, hippocampus, and prefrontal cortex of patients with mild cognitive impairment and Alzheimer＇s disease, and brain network-connection strength, network efficiency, and nodal attributes are abnormal. However, existing research has only analyzed the differences between these patients and normal controls. In this study, we constructed brain networks using resting-state functional MRI data that was extracted from four populations （nor- mal controls, patients with early mild cognitive impairment, patients with late mild cognitive impairment, and patients with Alzheimer＇s disease） using the Alzheimer＇s Disease Neuroimaging Initiative data set. The aim was to analyze the characteristics of resting-state functional neural networks, and to observe mild cognitive impairment at different stages before the transformation to Alzheimer＇s disease. Results showed that as cognitive deficits increased across the four groups, the shortest path in the rest- ing-state functional network gradually increased, while clustering coefficients gradually decreased. This evidence indicates that dementia is associated with a decline of brain network efficiency. In addi- tion, the changes in functional networks revealed the progressive deterioration of network function across brain regions from healthy elderly adults to those with mild cognitive impairment and AIz- heimer＇s disease. The alterations of node attributes in brain regions may reflect the cognitive functions in brain regions, and we speculate that early impairments in memory, hearing, and language function can eventually lead to diffuse brain injury and other cognitive impairments.展开更多
During 1979–2004, the East Asian summer precipitation has experienced another significant decadal shift around the early 1990 s. Based on three radiosonde temperature datasets and four reanalysis datasets, this paper...During 1979–2004, the East Asian summer precipitation has experienced another significant decadal shift around the early 1990 s. Based on three radiosonde temperature datasets and four reanalysis datasets, this paper examines the decadal change of the East Asian summer tropospheric temperature around the early 1990 s. The results show that the meridional gradient of layer mean upper tropospheric temperature for 200–500 h Pa(here after UTT, UTT is upper tropospheric temperature) also underwent an obvious decadal decrease around 1992. The tropospheric temperature south to 35°N becomes decadal cooling, centered along the Yangtze River Valley, while the tropospheric temperature north to 35°N shows a decadal warming, centered in Northwest China-Mongolia. JRA-25 reanalysis is better than the other reanalysis datasets in revealing this decadal change. This decadal shift of East Asian summer UTT may be ascribed to the decadal change of the ENSO period from low-frequency oscillation(4–6 yr) to quasi-biennial oscillation since 1992. It behaves as an increase of ENSO developing events and a reduction of ENSO decaying events. It leads to stronger forcing of ENSO developing summer and weaker forcing of ENSO decaying summer, leading to the dominant role of monopole cooling mode of East Asian UTT after 1992, in contrast to the dominant role of dipole mode of East Asia UTT before 1992. The summer UTT difference between 1993–2004 and 1979–1992 shows a "South cooling-North Warming" pattern, and thereby contributes to the interdecadal decrease of East Asian summer UTT meridional gradient around 1992.展开更多
I. IntroductionBeginning in the early 1980’s short-run macro policy in China moved away from direct government control of household and enterprise spending via largely administrative decree to more indirect control o...I. IntroductionBeginning in the early 1980’s short-run macro policy in China moved away from direct government control of household and enterprise spending via largely administrative decree to more indirect control of spending using conventional western monetary and fiscal policy instruments operating in an increasingly, although never completely, free and well-developed market setting. The initial theoretical basis for macro policy-making is best described as naive Monetarism, placing almost exclusive emphasis on monetary as opposed to展开更多
目的:探讨妊娠晚期脐动脉收缩末期与舒张末期峰值比(S/D值)变化与子代早期生长发育的相关性。方法:回顾性分析2021年1-8月在中国解放军联勤保障部队第九〇八医院进行系统产检并能完整随访的83例产妇为研究对象,根据子代是否出现早期生...目的:探讨妊娠晚期脐动脉收缩末期与舒张末期峰值比(S/D值)变化与子代早期生长发育的相关性。方法:回顾性分析2021年1-8月在中国解放军联勤保障部队第九〇八医院进行系统产检并能完整随访的83例产妇为研究对象,根据子代是否出现早期生长发育异常分组,将出现早期生长发育异常者纳入研究组,将早期生长发育正常者纳入对照组,回顾性分析比较两组一般临床资料,并探讨妊娠晚期脐动脉S/D值变化与子代早期生长发育的相关性。结果:研究组空腹血糖(FPG)水平高于对照组,新生儿出生后1 min Apgar评分低于对照组,差异均有统计学意义(P<0.05);两组孕晚期搏动指数(PI)、阻力指数(RI)、S/D值均明显低于孕中期,但研究组孕晚期PI值、RI值、S/D值均高于对照组,差异均有统计学意义(P<0.05)。logistic回归分析显示,孕晚期PI、RI、S/D值、FPG水平是子代早期生长发育的危险因素(P<0.05),新生儿出生后1 min Apgar评分是子代早期生长发育的保护因素(P<0.05)。结论:孕晚期PI、RI、S/D值及FPG和新生儿出生后1 min Apgar评分均会对子代早期生长发育产生影响,且随着孕期增加,脐带PI值、RI值、S/D值均明显降低,临床可针对以上因素对妊娠晚期妇女进行干预,以降低子代早期生长发育异常的发生率。展开更多
基金supported by the National Basic Research Program of China (Grant No. 2010CB950400)
文摘The Walker circulation is one of the major components of the large-scale tropical atmospheric circulation and variations in its strength are critical to equatorial Pacific Ocean circulation. It has been argued in the literature that during the 20th century the Walker circulation weakened, and that this weakening was attributable to anthropogenic climate change. By using updated observations, we show that there has been a rapid interdecadal enhancement of the Walker circulation since the late 1990s. Associated with this enhancement is enhanced precipitation in the tropical western Pacific, anomalous westerlies in the upper troposphere, descent in the central and eastern tropical Pacific, and anomalous surface easterlies in the western and central tropical Pacific. The characteristics of associated oceanic changes are a strengthened thermocline slope and an enhanced zonal SST gradient across the tropical Pacific. Many characteristics of these changes are similar to those associated with the mid-1970s climate shift with an opposite sign. We also show that the interdecadal variability of the Walker circulation in the tropical Pacific is inversely correlated to the interdecadal variability of the zonal circulation in the tropical Atlantic. An enhancement of the Walker circulation in the tropical Pacific is associated with a weakening zonal circulation in the tropical Atlantic and vise versa, implying an inter-Atlantic-Pacific connection of the zonal overturning circulation variation. Whether these recent changes will be sustained is not yet clear, but our research highlights the importance of understanding the interdecadal variability, as well as the long-term trends, that influence tropical circulation.
文摘The goal of this research is to describe and analyze women’s wear in the late Qing Dynasty andearly Republic Period(late 19th c.—early 20th c.),with an emphasis on the daily informal orsemi-formal wear,though some formal or ceremonial costumes such as wedding dress will also beincluded.This study will use Chinese costumes and textiles from many museums to fill in theblanks left by previous research and to give a more detailed and accurate description.It will alsouse historical documents to find the original names of these items and to illustrate a general conceptof their usage on different occasions.The different categories of women’s wear will be described in the following order:①robes orcoats;②jackets;③waistcoats or vests;④skirts;⑤pants and leggings;⑥shoes and socks;⑦headdresses;and⑧others.Of every category,the textiles,decoration,cut,form,style,colourand motif will be discussed.The way in which these items were combined will also be discussed.The comparison between women’s wear and men’s wear,women’s and children’s informal andformal dress will be given.Here are some tentative conclusions.First,the Manchu and Han style coexisted and mixedwith each other and were worn by both Manchu and Han women.Second,the basic silhouettesand cuts were relatively stable and conventional,while the decorations and details(openings,fasten-ings,pleats,vents,collars and hemlines)were different.The former represented accepted socialstandards while the latter could be a matter of personal taste.Third,women’s wear in that periodwere highly stylized,miscellaneous,elaborate,detailed,multicolored and multi-thematic.
文摘Extensive organic-matter （OM） rich facies （black shales） occur in the Ordo-Silurian boundary successions in the Yangtze area, South China. To investigate the redox changes of the Yangtze Sea during the Ordo-Silurian transition, two OM sections （Wangjiawan in Yichang, Hubei Province, and Sanjiaguan in Zhangjiajie, Hunan Province） straddling the Ordo-Silurian boundary are studied. The measurements finished in this study include contents of the total organic carbon （TOC）, pyrite sulphur, and different species of Fe, including dithionite-extractable Fe （FED）, pyrite Fe （FeP）, HCl-extractable Fe （FeH）, and total Fe （FeT）, in black shales, as well as other redox proxies, such as the SIC ratio, the ratio between highly reactive Fe （FeHR = FeD ＋ FeP） and FeT, and the FeP/（FeP ＋ FeH） ratio, known as the degree of pyritization （DOP）. In the Wangjiawan section, the Middle Ashgill sediments have high FeHR/FeT ratios （0.20-0.77; avg. 0.45）, high DOP values （0.21-0.72; avg. 0.54）, and a relatively constant sulfur content independent of the organic carbon content. By the contrast, the mid-early Hirnantian deposits generally have low FeHR/FeT ratios （0.10-0.35; avg. 0.21）, low DOP values （0.11- 0.40; avg. 0.28）, and SIC values are clustering on the normal marine value （SIC = 0.36）. The late Hirnantian and early Rhuddanian deposits, similar to those of the Middle Ashgill deposits, are characterized by high FeHR/FeT ratios （0.32-0.49; avg. 0.41）, high DOP values （0.46-0.68; avg. 0.53） and fairly constant sulfur contents. These data suggest the occurrences of marine anoxia on the Yangtze Sea shelf during intervals of the Mid Ashgill, Late Hirnantian and Early Rhuddanian, and ventilated and oxygenated marine conditions during the mid-early Hirnantian time. The mid-early Hirnantian ventilated event was concomitant with the global glacial period, likely resulted from the glacio-eustatic sea-level fall and subsequent circulation of cold, dense oxygenated waters upon the shelf seabed. Accordingly, the abrupt change from oxygenated to anoxic marine waters from the late Hirnantian and the early Rhuddanian were resulted from the post-glacial rise of eustatic sea level. Combined with the data from Sanjiaguan section near the subemergent highland, salinity stratification of water columns are strongly evidenced by very low S/C ratios （ 0.00-0.08, avg. 0.02）, low FeHR/FeT ratios （0.10-0.37, avg. 0.27）, low DOP values （0.01-0.27, avg. 0.10）, and TOC contents （0.72%-4.27%, avg. 2.55%）. Under this circumstance, the anoxic water columns could have formed beneath the halocline, above which desalinized waters formed. In the Wangjiawan section, TOC contents are generally high （0.94- 9.32%, avg. 4.44%）, but low （0.35%-2.12%, avg. 1.29%） in the mid-early Hirnantian that is coincident with the oceanic oxic stage, together with relation of the organic contents to the stratal thickness, suggesting that the accumulation of the organic matter was mainly controlled by the oxygen levels of the water columns; on the other hand, productivity and depositional rate may also have played a role in the organic accumulation and preservation.
基金Project supported by the China Climbing Project "Formation, Evolution, and Environmental Change and Ecosystem of the Qinghai-Xizang Plateau".
文摘Based on monthly mean temperature and precipitation, the changing processes and tendencies of temperature and precipitation in Qinghai-Xizang Plateau from 1950s to the early 1990s are analysed. The change of temperature in the past 40 a is almost unanimous on the spatial scale. The first area becoming warmer is the southeastern Tibet. The plateau is divided into 5 parts according to the change of temperature, and 9 parts according to the change of precipitation. For the past 40a some area has been warmer and drier, others warmer and wetter.
基金sponsored by the National Natural Science Foundation of China,No.61070077,61170136,61373101the Natural Science Foundation of Shanxi Province,No.2011011015-4Beijing Postdoctoral Science Foundation,No.Q6002020201201
文摘Brain structure and cognitive function change in the temporal lobe, hippocampus, and prefrontal cortex of patients with mild cognitive impairment and Alzheimer＇s disease, and brain network-connection strength, network efficiency, and nodal attributes are abnormal. However, existing research has only analyzed the differences between these patients and normal controls. In this study, we constructed brain networks using resting-state functional MRI data that was extracted from four populations （nor- mal controls, patients with early mild cognitive impairment, patients with late mild cognitive impairment, and patients with Alzheimer＇s disease） using the Alzheimer＇s Disease Neuroimaging Initiative data set. The aim was to analyze the characteristics of resting-state functional neural networks, and to observe mild cognitive impairment at different stages before the transformation to Alzheimer＇s disease. Results showed that as cognitive deficits increased across the four groups, the shortest path in the rest- ing-state functional network gradually increased, while clustering coefficients gradually decreased. This evidence indicates that dementia is associated with a decline of brain network efficiency. In addi- tion, the changes in functional networks revealed the progressive deterioration of network function across brain regions from healthy elderly adults to those with mild cognitive impairment and AIz- heimer＇s disease. The alterations of node attributes in brain regions may reflect the cognitive functions in brain regions, and we speculate that early impairments in memory, hearing, and language function can eventually lead to diffuse brain injury and other cognitive impairments.
基金supported by the National Natural Science Foundation of China(Grant Nos.41305072,41330423,41023002)the"Strategic Priority Research Program-Climate Change:Carbon Budget and Related Issues"of the Chinese Academy of Sciences(Grant No.XDA05110301)the Open Program of NUIST(Grant No.KLME1306)
文摘During 1979–2004, the East Asian summer precipitation has experienced another significant decadal shift around the early 1990 s. Based on three radiosonde temperature datasets and four reanalysis datasets, this paper examines the decadal change of the East Asian summer tropospheric temperature around the early 1990 s. The results show that the meridional gradient of layer mean upper tropospheric temperature for 200–500 h Pa(here after UTT, UTT is upper tropospheric temperature) also underwent an obvious decadal decrease around 1992. The tropospheric temperature south to 35°N becomes decadal cooling, centered along the Yangtze River Valley, while the tropospheric temperature north to 35°N shows a decadal warming, centered in Northwest China-Mongolia. JRA-25 reanalysis is better than the other reanalysis datasets in revealing this decadal change. This decadal shift of East Asian summer UTT may be ascribed to the decadal change of the ENSO period from low-frequency oscillation(4–6 yr) to quasi-biennial oscillation since 1992. It behaves as an increase of ENSO developing events and a reduction of ENSO decaying events. It leads to stronger forcing of ENSO developing summer and weaker forcing of ENSO decaying summer, leading to the dominant role of monopole cooling mode of East Asian UTT after 1992, in contrast to the dominant role of dipole mode of East Asia UTT before 1992. The summer UTT difference between 1993–2004 and 1979–1992 shows a "South cooling-North Warming" pattern, and thereby contributes to the interdecadal decrease of East Asian summer UTT meridional gradient around 1992.
文摘I. IntroductionBeginning in the early 1980’s short-run macro policy in China moved away from direct government control of household and enterprise spending via largely administrative decree to more indirect control of spending using conventional western monetary and fiscal policy instruments operating in an increasingly, although never completely, free and well-developed market setting. The initial theoretical basis for macro policy-making is best described as naive Monetarism, placing almost exclusive emphasis on monetary as opposed to
文摘目的:探讨妊娠晚期脐动脉收缩末期与舒张末期峰值比(S/D值)变化与子代早期生长发育的相关性。方法:回顾性分析2021年1-8月在中国解放军联勤保障部队第九〇八医院进行系统产检并能完整随访的83例产妇为研究对象,根据子代是否出现早期生长发育异常分组,将出现早期生长发育异常者纳入研究组,将早期生长发育正常者纳入对照组,回顾性分析比较两组一般临床资料,并探讨妊娠晚期脐动脉S/D值变化与子代早期生长发育的相关性。结果:研究组空腹血糖(FPG)水平高于对照组,新生儿出生后1 min Apgar评分低于对照组,差异均有统计学意义(P<0.05);两组孕晚期搏动指数(PI)、阻力指数(RI)、S/D值均明显低于孕中期,但研究组孕晚期PI值、RI值、S/D值均高于对照组,差异均有统计学意义(P<0.05)。logistic回归分析显示,孕晚期PI、RI、S/D值、FPG水平是子代早期生长发育的危险因素(P<0.05),新生儿出生后1 min Apgar评分是子代早期生长发育的保护因素(P<0.05)。结论:孕晚期PI、RI、S/D值及FPG和新生儿出生后1 min Apgar评分均会对子代早期生长发育产生影响,且随着孕期增加,脐带PI值、RI值、S/D值均明显降低,临床可针对以上因素对妊娠晚期妇女进行干预,以降低子代早期生长发育异常的发生率。
