东亚-澳大利西亚候鸟迁飞区中杓鹬 的迁徙追踪

追踪候鸟的迁徙活动是全面认识其生活史年周期的重要途径。中杓鹬(Numeniusphaeopus)在全球广泛分布,但在东亚-澳大利西亚候鸟迁飞区的迁徙活动一直缺乏追踪研究。2018年2月,在澳大利亚西北部的布鲁姆为捕捉到的中杓鹬成鸟佩戴平台发射终端或全球定位系统-全球移动通讯系统追踪器,以确定其迁徙日程、迁徙路线以及迁徙停歇地和繁殖地的地理位置。我们从成功追踪的7只个体获取了6 378条精度高于1 km的位点数据。分析结果表明,在春季,中杓鹬的迁徙时长为(36±4)d,其间在1～3个迁徙停歇地的停留日期为(23±2)d,从越冬地到繁殖地的迁徙距离为(9 795±346)km(n=7)。追踪的中杓鹬在俄罗斯东部和中部区域繁殖,不同个体的繁殖地纬度相近而经度范围较广。在秋季,中杓鹬的迁徙时长为(90±27)d,相比春季迁徙时长更长;其间,在2～4个迁徙停歇地停留(79±29)d,从繁殖地到越冬地的迁徙距离为(10 101±520)km(n=5)。无论在春季还是秋季迁徙,迁徙停歇地广泛分布于东亚、东南亚沿海及内陆区域。大部分个体春季和秋季的迁徙路线相近,成功追踪的个体均在秋季返回了上一年的越冬地,这表明中杓鹬对越冬地具有很高的忠诚度。     

云南大山包越冬黑颈鹤迁徙路线的卫星跟踪

2005年2月26日和3月1日在云南省昭通大山包黑颈鹤国家级自然保护区,分别为4只越冬黑颈鹤佩戴卫星信号发射器(PTTs),跟踪研究其迁徙路线和迁徙停歇地。2005年春季迁徙中,有2只跟踪黑颈鹤到达繁殖地,其中1只黑颈鹤在2005年11月和2006年3月分别完成从繁殖地返回越冬地和从越冬地再次到达繁殖地的迁徙过程。2只春季迁徙黑颈鹤的迁徙路线大致相同——沿着长江上游金沙江、大渡河一直向北到达黄河上游白河及黑河沿岸若尔盖湿地内。春季迁徙过程中,途中停歇3—4次,总迁徙距离是674—713km,迁徙全程所用时间3—4天。秋季迁徙全程所用时间8天。在4个PTTs工作期间,共确定有13个黑颈鹤迁徙停歇地,其中11个停歇地在河流滩地;其他2个停歇地在高山湖泊附近。总体上,黑颈鹤一般选择海拔在1900m以上湖泊、河流等湿地内,距离耕地较近且人、畜干扰较少的栖息地停歇。     

东方白鹳幼鸟渤海湾越冬群体的迁徙策略

东方白鹳(Ciconia boyciana)主要在俄罗斯远东和中国东北繁殖, 在中国主要有两个越冬群体(长江越冬群体, 迁徙距离约2,600 km; 渤海湾越冬群体, 迁徙距离约1,500 km)。本文基于2016-2018年的卫星追踪数据(N = 14), 分析了渤海湾越冬群体幼鸟春季和秋季的迁徙策略和利用风的方式, 总结了850 mb压力下风速和风向对日迁徙飞行速度的影响。该群体春秋两季迁徙距离相似, 但春季的顺风条件(2.2 ± 6.3 m/s)显著优于秋季的逆风条件(-2.4 ± 4.1 m/s, P < 0.05), 这使得春季迁徙飞行速度(280.4 ± 62.0 km/d)显著快于秋季(185.5 ± 72.0 km/d, P < 0.05), 春季迁徙飞行时间(5.9 ± 2.5 d)显著短于秋季(10.3 ± 6.5 d, P < 0.05); 同时, 春季停歇时间(5.4 ± 9.7 d)短于秋季(17.8 ± 18.2 d, P = 0.05)。基于以上原因, 东方白鹳春季迁徙持续时间(11.2 ± 8.7 d)显著短于秋季(28.0 ± 21.2 d, P < 0.05)。渤海湾越冬群体幼鸟迁徙时, 春季利用顺风更快到达度夏地, 秋季逆风迁徙, 迁徙飞行速度慢, 迁徙飞行时间和停歇时间长。因此, 东方白鹳迁徙时虽然主要利用上升热气流翱翔, 但顺风也是其成功迁徙的有利因素。     

云南大山包越冬黑颈鹤迁徙路线的卫星跟踪

2005年2月26日和3月1日在云南省昭通大山包黑颈鹤国家级自然保护区，分别为4只越冬黑颈鹤佩戴卫星信号发射器（PTTs），跟踪研究其迁徙路线和迁徙停歇地。2005年春季迁徙中，有2只跟踪黑颈鹤到达繁殖地，其中1只黑颈鹤在2005年11月和2006年3月分别完成从繁殖地返回越冬地和从越冬地再次到达繁殖地的迁徙过程。2只春季迁徙黑颈鹤的迁徙路线大致相同——沿着长江上游金沙江、大渡河一直向北到达黄河上游白河及黑河沿岸若尔盖湿地内。春季迁徙过程中，途中停歇3—4次，总迁徙距离是674—713 km，迁徙全程所用时间3—4天。秋季迁徙全程所用时间8天。在4个PTTs工作期间，共确定有13个黑颈鹤迁徙停歇地，其中11个停歇地在河流滩地；其他2个停歇地在高山湖泊附近。总体上，黑颈鹤一般选择海拔在1 900 m以上湖泊、河流等湿地内，距离耕地较近且人、畜干扰较少的栖息地停歇。     

基于卫星跟踪的洞庭湖越冬小天鹅迁徙路线研究

掌握洞庭湖越冬小天鹅Cygnus columbianus的迁徙行为和规律,明确迁徙路线和停歇地,是小天鹅栖息地恢复研究及保护的基础。2014—2017年,在湖南东洞庭湖国家级自然保护区对18只小天鹅进行卫星跟踪,收集了38 882条定位数据。本研究确定了小天鹅西线、中线和东线3条迁徙路线,其中,新发现的西线沿我国湖北、河南、山西、陕西、内蒙古,以及蒙古国、哈萨克斯坦,抵达俄罗斯亚马尔-涅涅茨自治区北部靠近喀拉海的北极苔原。西线春季迁徙距离为6 715 km,平均迁徙速度为21.52 km·h~(-1),秋季迁徙距离为7 467 km,平均迁徙速度为32.75 km·h~(-1)。中线春季迁徙距离为2 083 km,平均迁徙速度为28.93 km·h~(-1)。东线春季迁徙距离为5 965~6 351 km,平均迁徙速度为(28.71±0.95)km·h~(-1),秋季迁徙距离为5 101~5 331 km,平均迁徙速度为(29.15±3.65)km·h~(-1)。小天鹅春季迁徙进程慢于秋季,迁徙途中的最大飞行速度达133.3 km·h~(-1)。内蒙古自治区的黄河湿地和大兴安岭两侧河谷湿地是迁徙途中的重要中转站,小天鹅在此停歇15 d以上。本研究有助于了解小天鹅对栖息环境的偏好及迁徙路线选择策略,为禽流感等疾病传播和防控提供科学依据。     

卫星跟踪河北猎隼的秋季迁徙路线

猎隼（Falco cherrug）是国家Ⅱ级重点保护野生动物,IUCN物种红色名录濒危物种。为探究猎隼的迁徙规律,2018年9月26日在河北省保定市成功为1只猎隼佩戴了卫星追踪器,对其迁徙活动进行了跟踪。此猎隼个体的秋季迁徙路线涉及河北省、内蒙古自治区、山西省、陕西省、甘肃省、青海省6个省区,自东向西迁徙,越冬地为甘肃省白银市平川区。迁飞过程分为三个阶段,即放飞阶段、游荡期和迁飞期,三个阶段的飞行距离分别为297.62 km、1 129.69 km和2 040.9 km。此猎隼个体每天的飞行时段为（7:33 ± 2:01）时到（18:12 ± 1:09）时,即在白天飞行。平均日飞行时间为（10.44 ± 1.76）h,一天中平均飞行速度有三个高峰,分别为9:00、14:00和18:00时。迁飞过程中的平均飞行速度为（45.77 ± 20.88）km/h,平均日飞行距离（188.65 ± 113.90）km。此猎隼个体在越冬地晚间没有固定的休息点,休息地的海拔在1 500 ~ 2 000 m的位点较多,90%的活动区域面积为85.5 km2。2019年3月7日发现此猎隼个体被电死并悬挂在一根电线杆上,漏电电线杆是猎隼栖息的死亡陷阱。     

滦河上游——白枕鹤西部种群的重要停歇地

白枕鹤(Grus vipio)为国家II级重点保护野生动物, 被IUCN列为易危(VU)物种。白枕鹤西部种群繁殖于中蒙俄交界处的达乌尔地区, 数量呈下降趋势。我们于2017-2018年在蒙古国东部给白枕鹤西部种群的50只个体佩戴了GPS-GSM跟踪设备。截至2019年5月, 获得春季和秋季迁徙路径各48条。分析结果显示: 春季91.67%和秋季72.91%的跟踪个体在滦河上游(河北省沽源-内蒙古正蓝旗-多伦区域)停歇, 春季停留时间36.16 ± 15.00天、秋季20.26 ± 11.08天, 分别占春季和秋季迁徙时间的75%和67%, 确定了这一区域是西部种群迁徙途中最重要的停歇地。迁徙路线栖息地选择模型结果显示, 白枕鹤常在距离湖泊较近(< 210 km)、海拔1,200-1,500 m, 且坡度小(< 1°)的区域停歇。而滦河上游和整条迁徙路线停歇位点比较的模型结果显示, 滦河上游停歇地的海拔1,200-1,500 m与整条迁徙路线栖息地选择模型的结果一致; 此外这个区域离河流更近(< 70 km), 不仅有湿地和水体的栖息环境, 还有草地和农田可供觅食和栖息。保护空缺分析发现滦河上游现有四处保护地, 但在保护地内的迁徙停歇点不超过总位点的1.63%。综上, 我们建议将滦河上游整体纳入保护地体系进行管理, 为这一受胁物种及其栖息地管理和保护提供可靠保障。     

迁徙鸟类对中途停歇地的利用及迁徙对策

中途停歇地是迁徙鸟类在繁殖地和非繁殖地之间的联系枢纽,对于迁徙鸟类完成其完整的生活史过程具有重要作用。从鸟类的迁徙对策、中途停歇地的选择、鸟类在中途停歇地的停留时间、体重变化和种群特征以及中途停歇地的环境状况等方面,回顾了中途停歇生态学在近年来的研究进展,并提出了在迁徙对策理论的实验研究,小型鸟类在中途停歇地的停歇时间及体重变化的准确确定等目前有待解决的问题。     

卫星跟踪中蒙之间秃鹫春季迁徙路线及活动区域

秃鹫(Aegypius monachus)被世界自然保护联盟(IUCN)列为近危物种。每年冬季或者早春在渤海湾都会救护到因体质较弱而无法飞行的秃鹫,为了对秃鹫及其迁徙路线进行更有效的保护,于2016年春季对两只救护放飞秃鹫(ID1051和ID2016),利用卫星跟踪技术研究其迁徙路线和活动区,旨在为秃鹫的救护和保护提供基础资料。结果表明,ID1051和ID2016都迁徙到蒙古国的布尔干省和后杭爱省交界处,行程分别为2 200 km和2 400 km。ID2016在度夏初期、中期和后期的活动区面积(50%Fixed Kernel),分别为31 261.01km^2、1 492.96 km2和11 027.70 km^2。秃鹫在迁徙过程中主要时间在静息,其次是飞行和寻觅行为。在0至7时和19至24时,即晨昏和夜间秃鹫都处于静止状态。从8时开始,秃鹫开始活动,并在12和13时达到活动高峰,随后活动逐渐趋缓,直至18时趋于静止状态。本文提供了秃鹫的春季迁徙路线以及重要中途停歇地,为秃鹫的救护和保护提供了基础资料。     

救护白鹤与野生白鹤迁徙路线和活动规律差异分析

受伤和体弱白鹤的救护及放归是白鹤保护的重要方式之一。2014—2016年间,先后对8只救护白鹤和2只野生白鹤进行环志并安装卫星跟踪器,根据所获得的卫星跟踪数据来分析比较救护白鹤与野生白鹤在秋季迁徙路线和在重要中途停歇地的最大日活动距离、活动区分布和面积、生境类型等方面的异同。结果显示,救护白鹤放归当年与放归次年以及救护白鹤放归当年与野生白鹤的秋季迁徙路线和活动规律之间存在明显差异,但救护白鹤放归次年与野生白鹤之间差异不明显。(1)放归当年,4只救护白鹤在农田和水塘停歇1个月左右,停歇时长明显高于野生白鹤和放归次年的救护白鹤。(2)救护白鹤放归当年在跨海方式、登陆地点、停歇地点以及登陆后的迁徙方向上表现出多样性和不确定性,其中部分个体在迁徙过程中有停顿徘徊、迷失迁徙方向的现象,且跨越渤海和大别山的距离大于放归次年的救护白鹤和野生白鹤。(3)救护白鹤放归后4天内每日最大活动距离小,而后高低分化明显,无明显规律,而救护白鹤放归次年的每日最大活动距离规律变化与野生白鹤较一致。(4)与救护白鹤放归次年以及野生白鹤的活动规律相比,救护白鹤放归当年的栖息地位点变化频繁,具体表现为生境类型选择的多样化,且无明显规律,同时活动区面积较小。探索救护白鹤放归野外后与野生白鹤迁徙路线和活动规律的差异,对救护白鹤的科学放归具有指导意义。     

Ageing index evolution in the Spanish population

Official statistics allow an analysis of the ageing index changes in the Spanish population from 1930 to 1975. During this period the ageing index values doubled from 19.11 to 38.60, the maximum increase having occurred between 1950 and 1960. Both birth and death rates lowered during the 45 years studid; however, the death rate decreased twice as fast. The natural increase rise was thus mainly due to a lower death rate. These data can explain a part of the ageing index transformation. By province, the ageing index range increased three-fold from 1930 to 1975. Some provinces showed an elevated index and others a reduced one. After 1960, extensive areas of inland Spain showed an older age structure because of emigration to industrialized towns.     

Effect of Dextran 500 on Radial Migration of Erythrocytes in Postcapillary Venules at Low Flow Rates

Recently, we reported that collision efficiency (fraction of total collisions that result in the formation of aggregates) between red blood cells was an important factor in the formation of aggregates in postcapillary venules. In the present study, we focus on how high molecular weight dextran influences the overall radial migration trend of red blood cells in the postcapillary venule along a longitudinal distance of 50 μm from the bifurcation which would in turn affect collision behavior of these cells. A radial migration index, which defines the extent of radial migration of individual cells relative to the vessel center, was found to have a larger magnitude after infusion of dextran (1.9 ± 2.73) compared to that before dextran infusion (1.48 ± 3.89). This implied that dextran-induced aggregation might provide an external force to actively move cells towards the centerline of the vessel, which could contribute to the greater number of red blood cells participating in collision (16% increase) and aggregate formation. Further analysis of the collision behavior of individual red blood cells revealed that collision frequencies of individual cells decreased from a wide range (1 to 14) to a narrow range (1 to 5) after dextran treatment, indicating the alteration of collision behavior of red blood cells by the presence of aggregates along the flow stream.     

小鼠胚胎干细胞对黑色素瘤细胞体外生物学行为的影响

探讨体外共培养环境中小鼠胚胎干细胞对小鼠黑色素瘤B16细胞的影响。建立C57BL/6小鼠胚胎干细胞系,通过小鼠胚胎干细胞与肿瘤细胞体外共培养模型观察小鼠胚胎干细胞对肿瘤细胞的形态及生长行为的影响,MTT法与transwell小室法分别检测共培养后肿瘤细胞粘附性、迁移性及侵袭性的变化。共培养中小鼠胚胎干细胞能够侵入并推开小鼠黑色素瘤细胞形成自己的生长空间,与对照组比较共培养后肿瘤细胞的粘附性、迁移性及侵袭性均显著降低(P<0.05,P<0.01)。结果表明体外共培养体系中小鼠胚胎干细胞能够侵袭肿瘤细胞,并降低细胞粘附、迁移及侵袭相关恶性生物学行为。     

The effects of large and small-scale random events on the synchrony of metapopulation dynamics: a theoretical analysis

We present an analysis of the conditions under which migration and global random factors may determine large scale synchrony in the dynamics of spatially structured populations. We derive an analytic approximation which describes how the desynchronizing influence of local environmental stochasticity combines with the synchronizing influences of larger scale environmental stochastic variation and migration to determine population cross correlation coefficients. Despite the simplifications made by this analysis, computer simulations show that the behaviour of more complicated models is well described by our approximation over considerable regions of parameter space. We conclude that population synchrony is largely determined by the coefficients of variation (CVs) of the local and larger scale stochastic processes, and that migration alone is only likely to maintain population synchrony when the CV of the local stochastic process is very small.     

骨髓间充质干细胞在大鼠体内的迁移研究

目的:将体外预先标记的骨髓间充质干细胞(mesenchymalstemcells,MSCs)移植到大鼠脑内观察细胞的存活和转归,从在体(invivo)角度阐明MSCs在中枢神经系统疾病细胞治疗中的潜在应用前景。首先用DiI在体外标记MSCs。将标记后的MSCs分别移植到大鼠纹状体和侧脑室,在移植后2w和4w灌杀动物,进行脑组织及脊髓的冰冻切片,在荧光显微镜下观察细胞的存活与转归。结果:移植到纹状体的MSCs可沿针道向周围实质迁移,迁移的最远距离可达0.2mm。并且,在大脑皮层及其他脑实质的血管壁、血管中以及血管周围还可见到标记细胞;而移植到侧脑室的MSCs则主要沿脑室系统迁移,细胞主要分布在移植侧侧脑室,对侧脑室与第四脑室也有分布,也有少量细胞沿侧脑室向周围实质迁移,迁移的最远距离为0.23mm。还可见到沿胼胝体向对侧脑室迁移的细胞流,甚至有个别细胞迁移至脊髓腰段。所有动物在细胞移植后4周均未发现肿瘤形成。结论:MSCs脑内移植后可以在中枢神经系统内存活并迁移,无致瘤性。结果提示骨髓间充质细胞是很多疾病细胞与基因治疗的有力工具。     

CXCR4 Receptor Overexpression in Mesenchymal Stem Cells Facilitates Treatment of Acute Lung Injury in Rats

Novel therapeutic regimens for tissue renewal incorporate mesenchymal stem cells (MSCs) as they differentiate into a variety of cell types and are a stem cell type that is easy to harvest and to expand in vitro. However, surface chemokine receptors, such as CXCR4, which are involved in the mobilization of MSCs, are expressed only on the surface of a small proportion of MSCs, and the lack of CXCR4 expression may underlie the low efficiency of homing of MSCs toward tissue damage, which results in a poor curative effect. Here, a rat CXCR4 expressing lentiviral vector was constructed and introduced into MSCs freshly prepared from rat bone marrow. The influence of CXCR4 expression on migration, proliferation, differentiation, and paracrine effects of MSCs was examined in vitro. The in vivo properties of CXCR4-MSCs were also investigated in a model of acute lung injury in rats induced by lipopolysaccharide. Expression of CXCR4 in MSCs significantly enhanced the chemotactic and paracrine characteristics of the cells in vitro but did not affect self-renewal or differentiation into alveolar and vascular endothelial cells. In vivo, CXCR4 improved MSC homing and colonization of damaged lung tissue, and furthermore, the transplanted CXCR4-MSCs suppressed the development of acute lung injury in part by modulating levels of inflammatory molecules and the neutrophil count. These results indicated that efficient mobilization of MSCs to sites of tissue injury may be due to CXCR4, and therefore, increased expression of CXCR4 may improve their therapeutic potential in the treatment of diseases where tissue damage develops.     

Mistrust,fragmented solidarity,and transnational migration: Colombians in New York City and Los Angeles

This article compares the transnational economic, political, and sociocultural relations of Colombian migrants residing in two different locations in the United States. The vast majority of these migrants are middle class and originally from large urban areas, which differs from the typical rural-origin migrants previously studied by transnational scholars. The analysis is based on theoretical developments from transnational studies and insights advanced by economic sociology. Our findings suggest that transnational relations and activities do not follow a linear path and are not necessarily and inevitably a progressive process. The reach, scope and effects of transnational activities are contingent on the interaction of multiple contextual (state of origin-migrants relations; state of origin relations with country of destination; context of reception of immigrants abroad) and group factors (size, class composition, mode of settlement).     

崇明东滩鸻鹬类迁徙路线的环志分析

崇明东滩为东亚-澳大利西亚鸻鹬类迁徙路线上的重要迁徙停歇地.本文通过分析崇明东滩回收的异地环志鸻鹬类记录及异地回收的崇明东滩环志的鸻鹬类记录,研究崇明东滩鸻鹬类的迁徙路线.1979～2008年间,崇明东滩共回收到来自澳大利亚西北部、澳大利亚维多利亚、美国阿拉斯加及新西兰北岛等17个国家与地区环志的鸻鹬类265只,包括大滨鹬(Calidris tenuirostris)、斑尾塍鹬(Limosa lapponica)、红腹滨鹬(C.canutus)等16种鸟类,其中春季北迁期间的记录占总数的93%;2003～2008年间,澳大利亚西北部、新西兰南岛、中国大陆及新西兰北岛等10个国家与地区回收到崇明东滩环志的大滨鹬、斑尾塍鹬、红腹滨鹬等12种鸟类,共计164只.在所有与崇明东滩鸻鹬类存在迁徙连接的20个国家和地区中,澳大利亚西北部的回收记录占全部回收记录的55%.根据斑尾塍鹬和红腹滨鹬不同亚种的越冬地分布,崇明东滩回收的斑尾塍鹬有L.l.menzbieri与L.l.baueri两个亚种,红腹滨鹬有C.a.piersmai和C.a.rogersi两个亚种.     

Molecular characterization and expression profiles of IscA1 gene in a long-distance migrant, Agrotis segetum

Cryptochrome (CRYs) proteins have been elucidated as the molecular basis for magnetoreception in Drosophila, and a putative magnetic receptor (named IscA1) protein may aslo be involved in sensing magnetic fields in Drosophila. However, whether IscA1 has a conserved role in diverse animals and functions in orientation during animal migration is unknown. Here we report on the cloning and sequencing of the IscA1 gene from Agrotis segetum, which encodes a predicted protein IscA1 that has 131 amino acids and two conserved iron-sulphur cluster binding domains. Multiple sequence alignment and phylogenetic analysis were used to show that IscA1 had a relatively high homology from species of Noctuoidea. Quantitative polymerase chain reaction showed that IscA1 was ubiquitously expressed in adult organs and, among all developmental stages, expression was higher in adults. When Agrotis segetum was exposed to 14?h light/10?h dark, IscA1 expression also showed daily oscillations, and constant light or dark disturbed these oscillations. IscA1 expression levels in a migratory population were higher than in a reared population and higher in a southward migratory population than in a northward. These findings suggest that the IscA1 gene in A. segetum might be associated with migration and provide a molecular basis for further study on the functions of IscA1 gene in magnetoreception and potential control of the turnip moth.