期刊文献+
共找到2,103篇文章
< 1 2 106 >
每页显示 20 50 100
Characteristics of Temperature Change in China over the Last 2000 years and Spatial Patterns of Dryness/Wetness during Cold and Warm Periods 被引量:10
1
作者 Quansheng GE Haolong LIU +2 位作者 Xiang MA Jingyun ZHENG Zhixin HAO 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2017年第8期941-951,共11页
This paper presents new high-resolution proxies and paleoclimatic reconstructions for studying climate changes in China for the past 2000 years. Multi-proxy synthesized reconstructions show that temperature variation ... This paper presents new high-resolution proxies and paleoclimatic reconstructions for studying climate changes in China for the past 2000 years. Multi-proxy synthesized reconstructions show that temperature variation in China has exhibited significant 50–70-yr, 100–120-yr, and 200–250-yr cycles. Results also show that the amplitudes of decadal and centennial temperature variation were 1.3℃ and 0.7℃, respectively, with the latter significantly correlated with long-term changes in solar radiation, especially cold periods, which correspond approximately to sunspot minima. The most rapid warming in China occurred over AD 1870–2000, at a rate of 0.56°± 0.42℃(100 yr)^(-1); however, temperatures recorded in the 20 th century may not be unprecedented for the last 2000 years, as data show records for the periods AD 981–1100 and AD1201–70 are comparable to the present. The ensemble means of dryness/wetness spatial patterns in eastern China across all centennial warm periods illustrate a tripole pattern: dry south of 25°N, wet from 25°–30°N, and dry to the north of 30°N. However, for all centennial cold periods, this spatial pattern also exhibits a meridional distribution. The increase in precipitation over the monsoonal regions of China associated with the 20 th century warming can primarily be attributed to a mega El Nino–Southern Oscillation and the Atlantic Multidecadal Oscillation. In addition, a significant association between increasing numbers of locusts and dry/cold conditions is found in eastern China. Plague intensity also generally increases in concert with wetness in northern China, while more precipitation is likely to have a negative effect in southern China. 展开更多
关键词 temperature change dry-wet spatial pattern cold and warm periods last 2000 years China
下载PDF
Subseasonal transition of Barents-Kara sea-ice anomalies in winter related to the reversed warm Arctic-cold Eurasia pattern 被引量:1
2
作者 Yijia Zhang Zhicong Yin Huijun Wang 《Atmospheric and Oceanic Science Letters》 CSCD 2023年第5期49-54,共6页
“暖北极-冷欧亚”模态(WACE)的次季节反转会触发中国东部冬季的极端冷/暖转换以及春季沙尘暴.在这一显著的高纬度大气模态反转的驱动下,巴伦支海-喀拉海(BKS)的海冰异常也表现出次季节转换.当北极变暖以及乌拉尔山高压增强时,BKS异常... “暖北极-冷欧亚”模态(WACE)的次季节反转会触发中国东部冬季的极端冷/暖转换以及春季沙尘暴.在这一显著的高纬度大气模态反转的驱动下,巴伦支海-喀拉海(BKS)的海冰异常也表现出次季节转换.当北极变暖以及乌拉尔山高压增强时,BKS异常向下的湍流热通量和增强的向下红外辐射有利于海冰融化;近地面的异常偏南风使海冰从薄冰区向多年冰区漂移,进一步扩大了开阔洋面.相反的机制出现在WACE反位相,导致BKS海冰异常偏多.当WACE次季节反转时,上述机制分别发生在前冬和后冬,使得BKS海冰异常出现显著的次季节转换.近10年随着WACE反转频率增多,BKS海冰前后冬的次季节变化增强.本文构建了WACE次季节反转的综合示意图,有助于更好地理解和预测中国东部极端气候. 展开更多
关键词 暖北极-冷欧亚 巴伦支海-喀拉海海冰 次季节变化 湍流热通量 海冰漂移
下载PDF
Construction Technology of Warm Mix Asphalt Pavement in Cold High-Altitude Areas
3
作者 Guangxi Wu 《Journal of Architectural Research and Development》 2023年第5期27-33,共7页
With the continuous development of domestic highway construction,highway civil engineering and service level quality have attracted much attention.Good pavement quality and high-quality service make people feel comfor... With the continuous development of domestic highway construction,highway civil engineering and service level quality have attracted much attention.Good pavement quality and high-quality service make people feel comfortable and smooth when traveling.High-quality pavement can significantly reduce the probability of traffic accidents.At present,there is a direct relationship between pavement quality and pavement construction operations.Carrying out pavement construction operations in cold high-altitude areas requires a reasonable selection of construction equipment and methods.The application of warm-mix asphalt pavement construction technology can ensure pavement quality.Therefore,this paper analyzes the advantages of warm-mix technology,the environmental characteristics of cold high-altitude areas,and construction preparations,and discusses the construction technology of warm-mix asphalt pavement in cold high-altitude areas in detail,to improve the overall road quality of cold high-altitude areas. 展开更多
关键词 cold high-altitude areas warm mix asphalt Pavement construction technology
下载PDF
Cold ischemia time in liver transplantation:An overview
4
作者 Manuela Cesaretti Alessandro Izzo +2 位作者 Roberta Anna Pellegrino Alessandro Galli Orestes Mavrothalassitis 《World Journal of Hepatology》 2024年第6期883-890,共8页
The standard approach to organ preservation in liver transplantation is by static cold storage and the time between the cross-clamping of a graft in a donor and its reperfusion in the recipient is defined as cold isch... The standard approach to organ preservation in liver transplantation is by static cold storage and the time between the cross-clamping of a graft in a donor and its reperfusion in the recipient is defined as cold ischemia time(CIT).This simple definition reveals a multifactorial time frame that depends on donor hepatectomy time,transit time,and recipient surgery time,and is one of the most important donor-related risk factors which may influence the graft and recipient’s survival.Recently,the growing demand for the use of marginal liver grafts has prompted scientific exploration to analyze ischemia time factors and develop different organ preservation strategies.This review details the CIT definition and analyzes its different factors.It also explores the most recent strategies developed to implement each timestamp of CIT and to protect the graft from ischemic injury. 展开更多
关键词 cold ischemia time Liver transplantation Organ donation Donation after cardiac death warm ischemia time Machine perfusion
下载PDF
Effects of cold preservation and warm reperfusion on rat fatty liver 被引量:3
5
作者 Sun B Jiang HC +2 位作者 Piao DX Qiao HQ Zhang L 《World Journal of Gastroenterology》 SCIE CAS CSCD 2000年第2期271-274,共4页
INTRODUCTIONAlthough liver transplantation for irreversible liverdiseases is increasingly prevalent worldwide,patientdie while waiting for donors because of organshortages.One important problem commonlyencountered is ... INTRODUCTIONAlthough liver transplantation for irreversible liverdiseases is increasingly prevalent worldwide,patientdie while waiting for donors because of organshortages.One important problem commonlyencountered is that fatty livers often affect theoutcome of liver transplantation.It is reported thatthe incidence of abnormal fatty livers in autopsiesafter accidental death ranged from 15% to 24%.Since fatty livers may result in a primarynonfunction (PNF)liver graft,which contributes 展开更多
关键词 FATTY LIVER cold PRESERVATION warm REPERFUSION rats
下载PDF
The 2020/21 Extremely Cold Winter in China Influenced by the Synergistic Effect of La Niña and Warm Arctic 被引量:10
6
作者 Fei ZHENG Yuan YUAN +8 位作者 Yihui DING Kexin LI Xianghui FANG Yuheng ZHAO Yue SUN Jiang ZHU Zongjian KE Ji WANG Xiaolong JIA 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2022年第4期546-552,共7页
In the first half of winter 2020/21,China has experienced an extremely cold period across both northern and southern regions,with record-breaking low temperatures set in many stations of China.Meanwhile,a moderate La ... In the first half of winter 2020/21,China has experienced an extremely cold period across both northern and southern regions,with record-breaking low temperatures set in many stations of China.Meanwhile,a moderate La Niña event which exceeded both oceanic and atmospheric thresholds began in August 2020 and in a few months developed into its mature phase,just prior to the 2020/21 winter.In this report,the mid−high-latitude large-scale atmospheric circulation anomalies in the Northern Hemisphere,which were forced by the negative phase of Arctic Oscillation,a strengthened Siberian High,an intensified Ural High and a deepened East Asian Trough,are considered to be the direct reason for the frequent cold surges in winter 2020/21.At the same time,the synergistic effect of the warm Arctic and the cold tropical Pacific(La Niña)provided an indispensable background,at a hemispheric scale,to intensify the atmospheric circulation anomalies in middle-to-high latitudes.In the end,a most recent La Niña prediction is provided and the on-coming evolution of climate is discussed for the remaining part of the 2020/21 winter for the purpose of future decision-making and early warning. 展开更多
关键词 extremely cold winter anomalous atmospheric circulation synergistic effect La Niña warm Arctic
下载PDF
Influence of Major Stratospheric Sudden Warming on the Unprecedented Cold Wave in East Asia in January 2021 被引量:6
7
作者 Yingxian ZHANG Dong SI +3 位作者 Yihui DING Dabang JIANG Qingquan LI Guofu WANG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2022年第4期576-590,共15页
An unprecedented cold wave intruded into East Asia in early January 2021 and led to record-breaking or historical extreme low temperatures over vast regions.This study shows that a major stratospheric sudden warming(S... An unprecedented cold wave intruded into East Asia in early January 2021 and led to record-breaking or historical extreme low temperatures over vast regions.This study shows that a major stratospheric sudden warming(SSW)event at the beginning of January 2021 exerted an important influence on this cold wave.The major SSW event occurred on 2 January 2021 and subsequently led to the displacement of the stratospheric polar vortex to the East Asian side.Moreover,the SSW event induced the stratospheric warming signal to propagate downward to the mid-to-lower troposphere,which not only enhanced the blocking in the Urals-Siberia region and the negative phase of the Arctic Oscillation,but also shifted the tropospheric polar vortex off the pole.The displaced tropospheric polar vortex,Ural blocking,and another downstream blocking ridge over western North America formed a distinct inverted omega-shaped circulation pattern(IOCP)in the East Asia-North Pacific sector.This IOCP was the most direct and impactful atmospheric pattern causing the cold wave in East Asia.The IOCP triggered a meridional cell with an upward branch in East Asia and a downward branch in Siberia.The meridional cell intensified the Siberian high and low-level northerly winds,which also favored the invasion of the cold wave into East Asia.Hence,the SSW event and tropospheric circulations such as the IOCP,negative phase of Arctic Oscillation,Ural blocking,enhanced Siberian high,and eastward propagation of Rossby wave eventually induced the outbreak of an unprecedented cold wave in East Asia in early January 2021. 展开更多
关键词 cold wave stratospheric sudden warming polar vortex Ural blocking Siberian high
下载PDF
Prolonging warm ischemia reduces the cold preservation limits of liver grafts in swine 被引量:5
8
《Hepatobiliary & Pancreatic Diseases International》 SCIE CAS 2006年第4期515-520,共6页
关键词 liver transplantation non-heart-beating DONOR warm ISCHEMIA cold preservation ISCHEMIA/REPERFUSION
下载PDF
The Medieval Warm Period and Little Ice Age in the Daihai Area, North China 被引量:2
9
作者 金章东 王苏民 《Chinese Journal Of Geochemistry》 EI CAS 2003年第4期330-336,共7页
Rb/Sr ratio, CaCO\-3 content, organic carbon (C\-\{org\}) concentration, magnetic susceptibility and clay mineralogy of 4.0 m sediments samples recovered from Daihai Lake, northern China, are presented in the paper. W... Rb/Sr ratio, CaCO\-3 content, organic carbon (C\-\{org\}) concentration, magnetic susceptibility and clay mineralogy of 4.0 m sediments samples recovered from Daihai Lake, northern China, are presented in the paper. Weathering and paleoclimatic change history during the last 2300 years is reconstructed in terms of the variations of Rb/Sr ratios in the sediment sequence, including the Little Ice Age and Medieval Warm Period. Our results suggest that the evolution processes of weathering and paleoclimate can be rebuilt in terms of the variations of Rb/Sr ratios in the lake sediment sequence, in combination with magnetic susceptibility, C\-\{org\}, \{CaCO\-3\} contents and clay mineralogy. 展开更多
关键词 closed LAKE RB/SR ratio chemical WEATHERING LITTLE Ice Age Medival warm period
下载PDF
Objective identification research on cold vortex and mid-summer rainy periods in Northeast China 被引量:1
10
作者 龚志强 封泰晨 房一禾 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第4期571-580,共10页
Considering the differences between the Northeast China Cold Vortex (CV) and the Mid-Summer (MS) rainy period and their corresponding atmospheric circulations are comprehensively analyzed, and the objective identi... Considering the differences between the Northeast China Cold Vortex (CV) and the Mid-Summer (MS) rainy period and their corresponding atmospheric circulations are comprehensively analyzed, and the objective identification methods of defining the annual beginning and ending dates of Northeast China CV and MS rainy periods are developed respectively. The annual beginning date of the CV (MS) rainy period is as follows. In a period from April to August, if daily regional mean precipitation ryi is larger than yearly regional mean precipitation R (or 2R) on a certain day, the station precipitation rs is larger than the station yearly mean precipitation (r/ (or 2(r)) in at least 50% of stations in Northeast China, and this condition is satisfied in the following 2 (7) days, then this date is defined as the beginning date of the CV (MS) rainy period. While the definition of the ending date of the MS rainy period shows the opposite process to its beginning date. With this objective identification method, the multi-year average (1981-2010) beginning date of the CV rainy period is May 3, the beginning date of the MS rainy period is June 27, the ending day of the CV rainy period is defined as the day before the beginning date of the MS rainy period, and the ending date of the MS rainy period is August 29. Meanwhile, corresponding anomaly analysis at a 500-hPa geopotential height, 850-hPa wind, Omega and relative humidity fields all show that the definitions of the average beginning and ending dates of the CV and MS rainy periods have a certain circulation meaning. Furthermore, the daily evolution of the CV index, meridional and zonal wind index, etc. all show that these objectively defined beginning and ending dates of the CV and MS rainy periods have climate significance. 展开更多
关键词 Northeast China cold vortex rainy period mid-summer rain period objective identification method
下载PDF
Molecular Mapping of QTLs for Cold Tolerance at the Budburst Period in Rice 被引量:1
11
作者 QIAOYong-li HANLong-zhi +3 位作者 ANYong-ping ZHANGYuan-yuan CAOGui-lan KohHee-jong 《Agricultural Sciences in China》 CAS CSCD 2004年第11期801-806,共6页
The quantitative trait loci (QTLs) for cold tolerance at the budburst period (CTBP) was identified using a F2:3 population including 200 lines derived from a cross of indica and japonica Milyang 23/Jileng 1. A molec... The quantitative trait loci (QTLs) for cold tolerance at the budburst period (CTBP) was identified using a F2:3 population including 200 lines derived from a cross of indica and japonica Milyang 23/Jileng 1. A molecular linkage map of 97 SSR markers was constructed using interval mapping and covered a total length of 1 357.3 cM with an average distance of 13.99 cM, between adjacent markers in rice genome. The CTBP of F3 lines was evaluated at 5℃, and the survival seedling rate after treating under low temperature at the budburst period was used as cold tolerance index for CTBP. A continuous distribution near to normal for CTBP was observed in F3 lines, CTBP is a quantitative trait which was controlled by some genes. Three QTLs on chromosomes 2, 4 and 7 which are associated with CTBP were detected on location of RM6-RM240, RM273-RM303, RM214-RM11, respectively, which explained the range of the observed phenotypic variance from 11.5 to 20.5%. qCTBP4 detected on RM273-RM303 of chromosome 4 explained 20.5% of the observed phenotypic variance. The effect of qCTBP4’s allelic gene comes from Jileng 1., MSc; Correspondence 展开更多
关键词 RICE cold tolerance at the budburst period (CTBP) Microsatellite marker QTL
下载PDF
Effects of a Traditional Japanese Medicine Goshajinkigan, Tokishigyakukagoshuyushokyoto on the Warm and Cold Sense Threshold and Peripheral Blood Flow 被引量:1
12
作者 Rika Tsukada Takuji Yamaguchi +3 位作者 Liu Hang Masako Iseki Hiroyuki Kobayashi Eiichi Inada 《Health》 2014年第8期757-763,共7页
The purpose of this study was to investigate the effects of a traditional Japanese medicine Goshajinkigan (TJ-107) and Tokishigyakukagoshuyushokyoto (TJ-38) on warm sense threshold, cold sense threshold and the periph... The purpose of this study was to investigate the effects of a traditional Japanese medicine Goshajinkigan (TJ-107) and Tokishigyakukagoshuyushokyoto (TJ-38) on warm sense threshold, cold sense threshold and the peripheral blood flow. 31 healthy volunteers (control group: 9people, TJ-107 group: 12 people, TJ-38group:10 people) were examined. Drugs administered 2.5 g a dose. Analysis was before and after 1 hour dosage. The warm and cold sense threshold in the thenar of the non-handedness site of these subjects was measured using a thermostimulator (Intercross-200, Intercross Co., Tokyo, Japan). The peripheral blood flow in the finger of the non-handedness site of these subjects was measured using a full-field laser perfusion imager (FLPI, Moor Instruments Ltd., England). Control: The vehicle had no significant effect on the warm sense threshold, cold sense threshold and the peripheral blood flow. TJ-107: The warm sense threshold and cold sense threshold were significantly decreased, and the reaction latency of cold sense was significantly shortening. The peripheral blood flow was significantly increased second and third finger at 115.6%, 119.3%, respectively. TJ-38: The cold sense threshold and the reaction latency of cold sense were significantly increased. The peripheral blood flow was significantly increased second and third finger with 114.3%, 112.8%, respectively. These results suggest that TJ-107 and TJ-38 have effects on the changed warm sense threshold, cold sense threshold and increased peripheral blood flow. 展开更多
关键词 A Traditional JAPANESE MEDICINE Goshajinkigan Tokishigyakukagoshuyushokyoto The warm and cold SENSE THRESHOLD PERIPHERAL Blood Flow
下载PDF
THE FREQUENCY CHARACTERISTICS OF WARM AND COLD EPISODES IN THE NIO REGIONS 被引量:9
13
作者 孙卫国 程炳岩 黄海仁 《Journal of Tropical Meteorology》 SCIE 2005年第2期200-205,共6页
On the basis of NOAA/CPC data of sea surface temperature anomaly in the Nio regions during Jan. 1950 – Dec. 2003, the wavelet power spectrum of SST were studied with significance and confidence testing at different... On the basis of NOAA/CPC data of sea surface temperature anomaly in the Nio regions during Jan. 1950 – Dec. 2003, the wavelet power spectrum of SST were studied with significance and confidence testing at different scales in this paper. It shows that the SST are provided with multi-time scales structure nested one another, and vary on scales of 2 – 7 years, 8 – 20 years and >30 years. The most significant variation of the warm and cold episodes is in the 4-year band of period. The power, frequency structure and confidence of the same episode are different in different Nio regions. The intensity of oscillations is increasing at low frequency bands and decreasing at high frequency bands from east to west in the Ni?o regions, especially after 1970. 展开更多
关键词 海洋气象 气候变化 冷热交替 SST 大气循环
下载PDF
Opposing Trends of Winter Cold Extremes over Eastern Eurasia and North America under Recent Arctic Warming 被引量:1
14
作者 Shuangmei MA Congwen ZHU 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2020年第12期1417-1434,共18页
Under recent Arctic warming,boreal winters have witnessed severe cold surges over both Eurasia and North America,bringing about serious social and economic impacts.Here,we investigated the changes in daily surface air... Under recent Arctic warming,boreal winters have witnessed severe cold surges over both Eurasia and North America,bringing about serious social and economic impacts.Here,we investigated the changes in daily surface air temperature(SAT)variability during the rapid Arctic warming period of 1988/89–2015/16,and found the daily SAT variance,mainly contributed by the sub-seasonal component,shows an increasing and decreasing trend over eastern Eurasia and North America,respectively.Increasing cold extremes(defined as days with daily SAT anomalies below 1.5 standard deviations)dominated the increase of the daily SAT variability over eastern Eurasia,while decreasing cold extremes dominated the decrease of the daily SAT variability over North America.The circulation regime of cold extremes over eastern Eurasia(North America)is characterized by an enhanced high-pressure ridge over the Urals(Alaska)and surface Siberian(Canadian)high.The data analyses and model simulations show the recent strengthening of the high-pressure ridge over the Urals was associated with warming of the Barents–Kara seas in the Arctic region,while the high-pressure ridge over Alaska was influenced by the offset effect of Arctic warming over the East Siberian–Chukchi seas and the Pacific decadal oscillation(PDO)–like sea surface temperature(SST)anomalies over the North Pacific.The transition of the PDO-like SST anomalies from a positive to negative phase cancelled the impact of Arctic warming,reduced the occurrence of extreme cold days,and possibly resulted in the decreasing trend of daily SAT variability in North America.The multi-ensemble simulations of climate models confirmed the regional Arctic warming as the driver of the increasing SAT variance over eastern Eurasia and North America and the overwhelming effect of SST forcing on the decreasing SAT variance over North America.Therefore,the regional response of winter cold extremes at midlatitudes to the Arctic warming could be different due to the distinct impact of decadal SST anomalies. 展开更多
关键词 daily surface air temperature variability extreme cold days Arctic warming eastern Eurasia North America
下载PDF
Onshore warm tongue and offshore cold tongue in the western Yellow Sea in winter:the evidence 被引量:2
15
作者 孙俊川 杨德周 +2 位作者 尹宝树 陈海英 冯兴如 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2018年第5期1475-1483,共9页
A winter onshore warm tongue extending from the Yellow Sea Warm Current to the southern Jiangsu coast, and an of fshore cold tongue extending from the southern Jiangsu coast to the southwest of Jeju Island(South Korea... A winter onshore warm tongue extending from the Yellow Sea Warm Current to the southern Jiangsu coast, and an of fshore cold tongue extending from the southern Jiangsu coast to the southwest of Jeju Island(South Korea), are newly identified based on the sea-surface temperature from satellite remote sensing, and further confirmed by the distribution of suspended sediments. In addition, there are two obvious thermal fronts associated with the onshore warm tongue and off shore cold tongue. The narrow gap between the two thermal fronts is supposed to be the pathway for the off shore transport of cold coastal water and suspended sediments. The concurrence of onshore warm and of fshore cold tongues suggests the concurrence of onshore and off shore currents in the western Yellow Sea in winter, which seems to be inconsistent with the previously accepted view that, in winter, the Yellow Sea Coastal Current flows from the Old Huanghe Delta to the southwest of Jeju Island. This distinctive phenomenon helps establish an updated view of the circulation in the western Yellow Sea in winter. 展开更多
关键词 卫星遥感 海面温度 黄海 暖流
下载PDF
Middle Holocene warm period and sea level high in coastal areas,North China 被引量:1
16
作者 孟广兰 韩有松 王少青 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2005年第2期252-258,共7页
Relevant geological, geographical, archaeological data were collected to study the characteristics of middle Holocene warm period and sea level high on North China coast. Middle Holocene climate and sea level change o... Relevant geological, geographical, archaeological data were collected to study the characteristics of middle Holocene warm period and sea level high on North China coast. Middle Holocene climate and sea level change on North China coast were correlated to warm marine environment events in about 8–3 ka B.P. The sea level in about 8 ka B.P. was higher than present mean sea level, then fluctuated for 5 000 years and after that it became even in 3 ka B.P. The highest sea level occurred in about 6–5 ka B.P.; the maximum was about 2–3 m and minimum was about 1–2 m. 展开更多
关键词 中全新世 中国北部海岸 海平面高度 暖周期
下载PDF
More than a simple egg:Underlying mechanisms of cold tolerance in avian embryos 被引量:1
17
作者 Ibrahim M.Ahmad Dongming Li 《Avian Research》 SCIE CSCD 2023年第2期267-280,共14页
Avian embryos,which develop within eggs,exhibit remarkable tolerance to extremely low temperatures.Despite being a common trait among all birds,the mechanisms underlying this cold tolerance in avian embryos remain lar... Avian embryos,which develop within eggs,exhibit remarkable tolerance to extremely low temperatures.Despite being a common trait among all birds,the mechanisms underlying this cold tolerance in avian embryos remain largely unknown.To gain a better understanding of this phenomenon and the coping mechanisms involved,we reviewed the literature on severe cold tolerance in embryos of both wild and domestic birds.We found that embryos of different bird orders exhibit tolerance to severe cold during their development.In response to cold stress,embryos slow down their heartbeat rates and metabolism.In severe cold temperatures,embryos can suspend these processes,entering a torpid-like state of cardiac arrest.To compensate for these developmental delays,embryos extend their regular incubation periods.Depending on their embryonic age,embryos of all bird species can tolerate acute severe cold regimes;only a few tolerate chronic severe cold regimes.We also discussed various extrinsic and intrinsic factors that affect the tolerance of bird embryos to low temperatures before and after incubation.Cold tolerance appears to be a heritable trait shared by wild and domestic embryos of all bird classes,regardless of egg size or development(altricial/precocial).Driven by environmental variability,cold tolerance in avian embryos is an optimal physiological and ecological strategy to mitigate the adverse effects of cold conditions on their development in response to fluctuating environmental temperatures. 展开更多
关键词 Acute cold tolerance Avian embryo Chronic cold tolerance Embryonic development Hatching success Incubation period
下载PDF
Arctic warming and its influence on East Asian winter cold events:a brief recap
18
作者 Seong-Joong KIM Baek-Min KIM 《Advances in Polar Science》 2018年第1期3-12,共10页
The rate of warming of Arctic surface temperature is about 2–3 times faster than the global mean surface warming. Increases of ice albedo feedback and water vapor as well as moisture intrusion from outside the Arctic... The rate of warming of Arctic surface temperature is about 2–3 times faster than the global mean surface warming. Increases of ice albedo feedback and water vapor as well as moisture intrusion from outside the Arctic all have major roles in this phenomenon. In contrast to this rapid Arctic warming, in recent decades, stronger cold air outbreaks have occurred more frequently during winter in East Asia than were recorded in the 1990s, resulting in severe socioeconomic impacts. A number of related studies have claimed the increased frequency of these stronger cold air outbreaks is linked to the amplified warming in the Arctic through complicated mechanisms. As there are time lags between the observed Arctic warming and East Asian cold weather response at various scales, understanding the entire chain of processes from the Arctic to East Asia has importance for forecasting winter weather in East Asia. There are two pathways linking Arctic warming with East Asian cold weather events. One is the synoptic-scale pathway in the lower troposphere via strengthening of the Siberian High initiated by Ural blocking. The other is the planetary-scale path through the stratosphere via activation of planetary waves and downward propagation, which weakens the polar vortex. This study briefly reviews the current understanding of the linkage mechanisms between Arctic warming and East Asian winter cold weather. 展开更多
关键词 Arctic warming East Asia cold surge linkage process synoptic response planetary response
下载PDF
Comparative Analysis of Strong Convection Process of Convective Cold Cloud and Convective Warm Cloud Type
19
作者 Yue Ni Yuan Su Jinqin Feng 《Journal of Geoscience and Environment Protection》 2018年第9期22-30,共9页
On the night of April 20, 2017, there was a heavy rain in Longyan City, accompanied by strong convective weather such as strong lightning, short-term heavy precipitation, and 6 - 8 thunderstorms. The three-hour rain i... On the night of April 20, 2017, there was a heavy rain in Longyan City, accompanied by strong convective weather such as strong lightning, short-term heavy precipitation, and 6 - 8 thunderstorms. The three-hour rain intensity and the six-hour rain intensity of Shanghang Tongxian Township and Nanyang Town were once in a century. Through the use of radar, radar wind profile and lightning locator data, the process can be divided into two phases: The first stage is the strong precipitation stage of Changting Datong Town during the 20 - 22 periods on the 20th. The process is accompanied by short-term heavy precipitation (59.7 mm/h), strong lightning activity, and 6 - 8 thunderstorm gales. It is a convective cold cloud dominated precipitation. The second stage is the strong precipitation stage of Shanghang Tongxian Township on the 21st, 02 - 04, and the short-term strong precipitation intensity reaches 75.7 mm/h, but the lightning and wind activity are weak, which is the convective warm cloud-oriented precipitation. There are significant differences in the strong convective weather between the two phases in the same background. The analysis shows that the strong echo of the first stage radar (above 60 dBz) is block-shaped southward, the speed of movement is fast, the height of the echo top is high, and the rear nascent monomer forms a train effect. In the second stage, the southwest-northeast-oriented convective zone moves to the northeast direction, forming the train effect of the echo zone. The center intensity is above 50 dBz, the echo top height is low, and the precipitation center moves slowly. This caused a large amount of accumulated rainfall. In this paper, the radar data is used to analyze the heavy rainfall process on the west coast of the straits, which has certain indication significance for the predictability of strong convective weather. 展开更多
关键词 Strong CONVECTION CONVECTIVE cold CLOUD Dominated PRECIPITATION CONVECTIVE warm CLOUD Dominant PRECIPITATION OBLIQUE Pressure
下载PDF
Assessment of Warm and Cold Ischemia on Functions of the Operated Kidney with <sup>99m</sup>Tc-DMSA in Renal Masses: A Prospective and Randomized Study
20
作者 Abdullah Demirtas Numan Baydilli +3 位作者 Nurettin Sahin Oguz Ekmekcioglu Deniz Demirci Atila Tatlisen 《Open Journal of Urology》 2013年第2期62-67,共6页
Objective: To examine the effect of warm and cold ischemia on functions of the operated kidney in cases with a normal contralateral kidney undergoing nephron sparing surgery. Methods: This study enrolled 40 patients w... Objective: To examine the effect of warm and cold ischemia on functions of the operated kidney in cases with a normal contralateral kidney undergoing nephron sparing surgery. Methods: This study enrolled 40 patients with a normal contralateral kidney and without a renal function threatening risk factor, who were operated with NSS. The patients were randomized at admission. They were divided into 2 equal groups as warm and cold ischemia. An ice application for 10 minutes was done to cold ischemia group after clamping renal artery. Renal functions were evaluated with Technesium-99m-Dimercaptosuccinic Acid (DMSA) and serum creatinine at the preoperative and postoperative (day 1, day 15, month 6, and month 12) period. Statistical analysis was done with Mann Whitney U test, Wilcoxon Signed Rank test, and Fredman test. A p value below 0.05 was considered statistically significant. Results: There were no significant differences between the groups in terms of age, body mass index, ischemia time, tumor size, amount of hemorrhage, and procedure time. Both groups had a significantly higher DMSA uptake at the preoperative period compared with the postoperative period (postoperative day 1, day 15, month 6, and month 12) (p 0.001). However, both groups had similar DMSA uptake results at the postoperative period. Preoperative and postoperative creatinine levels were not significantly different from each other in both groups. Conclusion: Based on tumor localization, nephron sparing surgery without use of superficial cooling appears as a viable option for small renal masses. 展开更多
关键词 cold ISCHEMIA TIMES NEPHRON Sparing Surgery Renal Cancer Technetium-99m-Dimercaptosuccinic Acid warm ISCHEMIA TIMES
下载PDF
上一页 1 2 106 下一页 到第
使用帮助 返回顶部