不同生境和季节社鼠与大林姬鼠的微生境选择比较

微生境选择分化是生境相似的物种间共存的重要原因。社鼠和大林姬鼠为北京东灵山地区常见鼠种,生境需求、活动节律及食物组成等相似,但二者共存的原因尚不清楚。2016—2017年,我们对北京东灵山地区社鼠和大林姬鼠的微生境选择进行了研究。不同季节和生境类型中,社鼠和大林姬鼠微生境选择存在明显分化。灌丛生境中,春季社鼠偏好于乔木密度、草本盖度更高和落叶盖度相对偏低的微生境,而大林姬鼠选择郁闭度、落叶盖度较高而草本盖度较低的微生境;主成分分析表明,地表覆盖物是影响二者微生境选择的主要因素;秋季社鼠喜好乔木种类多、灌木密度和草本盖度更高的微生境,而大林姬鼠选择乔木胸径、灌木距离、落叶盖度和空地比例更高的微生境,食物丰富度是影响社鼠和大林姬鼠微生境选择的主要因素。弃耕地生境中,春季社鼠倾向于灌木密度和草本盖度较高的微生境,而大林姬鼠首选郁闭度、乔木胸径、落叶盖度较大而草本盖度较低的微生境,地表覆盖物是影响二者微生境选择的主要因素;秋季社鼠偏好郁闭度和落叶盖度都相对较低的微生境,大林姬鼠则相反,食物多度是影响二者微生境选择的主要因素。次生林生境中,春季因样本量太少,未作分析;秋季社鼠优先选择灌木密度、灌木基径和草本盖度更高的微生境,大林姬鼠更倾向乔木胸径、落叶盖度较高,而灌木密度、草本盖度较低的微生境,地表覆盖物是影响二者微生境选择的主要因素。结果表明,不同生境和季节,两种鼠的微生境选择具有明显分化,这可能是二者共存的重要原因之一。     

江苏盐城黑紫鸥（Larus saundersi）繁殖微生境的选择

1999～2001年春夏对江苏盐城国家级自然保护区黑嘴鸥的繁殖微生境进行了调查,黑嘴鸥的繁殖生境包括碱蓬群落（Suaeda glauca）、獐毛群落（Aeluropus littoralis）和大米草群落（Spartina anglica）,通过生境可获得性与可利用性分析,得知黑嘴鸥营巢对碱蓬生境具有正选择性,对獐毛和大米草生境具有负选择性。对繁殖微生境选择研究的结果表明,黑嘴鸥繁殖微生境具有以下特征：植被高度5～25cm,植被盖度20%～60%,底栖生物量大于300g/m^2,距水源距离500～1000m,距人类活动干扰距离大于500m,滩涂开发和人为活动是影响盐城地区黑嘴鸥繁殖微生境选择的重要因素。本文对黑嘴鸥繁殖栖息地的保护和管理提出了一些建议。     

灌丛高度对啮齿动物贮藏和扩散辽东栎坚果的影响

本文选择高、矮两类灌丛生境, 于2002 年至2003 年在其中释放标记的辽东栎坚果, 并连续记录释放坚果的命运, 以了解生境差异对啮齿动物搬运、取食和贮藏辽东栎坚果的影响以及啮齿动物对微生境的选择等。研究结果表明, 大林姬鼠等啮齿动物对辽东栎坚果的短期取食非常强烈, 而分散贮藏的量则相对较少; 啮齿动物对辽东栎坚果的搬运距离在矮灌丛生境中显著大于高灌丛生境; 啮齿动物倾向于选择灌丛边缘和灌丛下方取食或贮藏辽东栎坚果, 这类微生境也有利于埋藏坚果的萌发。     

江苏盐城黑嘴鸥(Larus saundersi)繁殖微生境的选择

1999～2001年春夏对江苏盐城国家级自然保护区黑嘴鸥的繁殖微生境进行了调查。黑嘴鸥的繁殖生境包括碱蓬群落(Suaeda glauca)、獐毛群落(Aeluropus littoralis)和大米草群落(Spartina anglica)。通过生境可获得性与可利用性分析,得知黑嘴鸥营巢对碱蓬生境具有正选择性,对獐毛和大米草生境具有负选择性。对繁殖微生境选择研究的结果表明, 黑嘴鸥繁殖微生境具有以下特征：植被高度5～25 cm,植被盖度20％～60％,底栖生物量大于300 g/m²,距水源距离500～1000 m,距人类活动干扰距离大于500 m。滩涂开发和人为活动是影响盐城地区黑嘴鸥繁殖微生境选择的重要因素。本文对黑嘴鸥繁殖栖息地的保护和管理提出了一些建议。     

若尔盖湿地国家自然保护区三种无尾两栖类夏秋季生境选择

2004年8—9月在若尔盖湿地国家自然保护区采用样方法对高原林蛙(Ranakukunoris)、倭蛙(Nanoranapleskei)和岷山蟾蜍(Bufominshanicus)的生境选择性进行了研究。先设置16个50m×50m的样地,再在每个样地内分25个10m×10m的样方,测量每个样方中的12个生境因子(牧场性质、草本高度、草本盖度、牛粪数量、鼠兔洞口数量、鼢鼠土堆数量、地表温度、地表湿度、土壤温度、离小型水体距离、离大型水体距离、离道路距离)。结果表明:这3种两栖类均偏好离溪流、水塘等小型水体距离较近(≤100m)、离河流、湖泊等大型水体距离较远(>1000m)、适度放牧(牛粪数量1~20)以及无鼠兔(Ochotonasp·)洞口的生境。通过比较,发现高原林蛙和倭蛙显著选择夏牧场、草本高度5·1~10·0cm、离小型水体0~50m的生境,显著不选择鼢鼠土堆太多(>10)的生境;岷山蟾蜍对牧场性质、离道路距离无显著选择性,显著选择草本高度>20·0cm、离小型水体51~100m的生境,不选择无鼢鼠土堆的生境;高原林蛙显著选择离道路>50m的生境;倭蛙显著选择离道路0~50m的生境。3种两栖类在生境选择上产生了一定的分离,表明各自有着特殊的生境需求。判别分析表明,牧场性质、草本高度、地表湿度、土壤温度、鼢鼠土堆数量、离大或小型水体距离、离道路距离是区别3种两栖类生境选择的重要参数。     

同域分布红腹锦鸡和红腹角雉在不同空间尺度下的生境分化

生境分化是群落物种缓解种间竞争压力,实现同域稳定共存的重要途径,是群落生态学领域的重要研究内容。同域动物的生境分化是空间尺度依赖的生态过程,从不同空间尺度分层研究物种的生境分化,对于全面了解同域动物的共存模式和机制,以及实现多物种整合保护都具有重要意义。2018年1月至8月,在四川白水河国家级自然保护区对同域分布的红腹锦鸡(Chrysolophus pictus)和红腹角雉(Tragopan temmminckii)进行了野外调查,基于MaxEnt模型和样方法,从宏生境和微生境两个空间尺度对其生境分化进行了研究。结果显示:1)在宏生境尺度,两种雉类的适宜宏生境重叠面积达44.59 km~2,分别占红腹锦鸡和红腹角雉适宜宏生境面积的58.73%和44.3%,表明二者在宏生境尺度上没有发生明显的种间分化;2)微生境尺度是两种雉类生境分化的关键尺度,海拔、坡位、最近水源距离和乔木层盖度4个特征上的显著差异,使二者的微生境发生显著的种间分化;3)虽然在不同空间尺度下具有不同的分化程度和方式,但两种雉类在海拔适应性、人为干扰耐受性以及对水源的依赖性上的差异在两个尺度下表现出了一定的一致性。此外,基于二者生境需求的异同,提出了控制人为干扰、加强宣传教育、维持自然植被多样性和镶嵌格局等针对该区域雉类物种共同保护的建议。     

丹顶鹤春迁期觅食栖息地多尺度选择——以双台河口保护区为例

双台河口保护区是世界濒危鸟类丹顶鹤大陆种群西线群体不同生活史阶段的重要栖息地。2008-2010年3-4月,采用定点观察法、二维坐标法、方差分析、因子分析等方法对保护区内春迁期丹顶鹤觅食栖息地的多尺度选择进行了监测分析。研究结果表明：(1)春迁期,该保护区丹顶鹤觅食栖息地选择包括2个尺度3个选择,即大生境尺度内觅食生境类型选择和小生境尺度内觅食区选择、觅食微生境选择;(2)觅食生境类型偏好选择芦苇沼泽(90.00%),也偶选玉米地、泥滩、草甸等生境;(3)觅食区选择通过宏生境因子和干扰因子来判定,宏生境因子包括明水面、堤坝和火烧地,距离均在30m以内;干扰因子包括居民区和油田等强干扰因子和道路等弱干扰因子,均采取远离的方式进行回避,居民区保持在1km以上,油田保持在2km以上,道路保持在300-500m;(4)觅食微生境选择通过微生境因子来判定,包括植被高度、植被密度、植被直径等,选择盖度小(<5%)且植被高度小于喙长的区域觅食。     

完达山东部林区生境特征对东北林蛙产卵的影响

在研究人员逐渐将研究的焦点集中在栖息生境破碎化和生境丧失对在池塘繁育的两栖动物的影响方面。至今,许多研究已经评估了在多个空间尺度下生境因子对两栖类动物繁育池选择的影响。由于在1个繁育池内1只林蛙只产1团卵,因此利用繁育池内蛙卵团数与生境因子之间存在的内在联系建立生境选择函数模型,探究林蛙繁育期不同生境因子对东北林蛙种群大小的影响。从2012年到2014年5月初至7月末的东北林蛙繁育期,在完达山东部五泡林场,共调查了105个水池,93.33%的池塘中发现了林蛙卵团。在繁育池微生境尺度水平,广义可加模型分析表明,繁育池面积对东北林蛙卵团数产生积极影响,对林蛙卵团数的贡献为0.17;但林木郁闭度和繁育池水表面杂物盖度对林蛙卵团数产生负面影响,对林蛙卵团数贡献分别为-0.30和-0.43。在繁育池周围5km景观尺度水平,森林面积对蛙卵数产生积极影响,对GAM预测模型的贡献为17.99;公路干扰对蛙卵团数产生负面影响,随着距公路距离增加,林蛙卵团数增加,对GAM预测模型的贡献为1.40。研究结果表明,虽然在繁育池微生境尺度水平预测模型包含的变量较景观尺度水平预测模型包含的变量多,但两个模型对于预测林蛙个体产卵团数均有效。因此,可以认为,保护林蛙种群生存和繁育,需要优先保护面积为4—150 m~2,池内水表面有一定杂物覆盖(0—14%),林木郁闭度较小(约10%),森林覆盖率高,距公路较远的区域。     

基于4个线粒体基因的不同海拔高原林蛙群体遗传多样性研究

高原林蛙Rana kukunoris是中国特有的两栖动物,分布于青藏高原海拔2 000～4 400 m的湿润环境。为探究青藏高原的高原林蛙遗传多样性,将4个线粒体基因（COⅠ、cyt b、12S rRNA和16S rRNA）序列合并成联合数据集,对采自青海省4个海拔梯度（2 000 m、2 600 m、3 200 m和3 800 m）的100只高原林蛙个体进行测序分析。结果表明,2 000 m和2 600 m的高原林蛙群体的多态位点、单倍型多样性、核苷酸多样性和平均核苷酸差异数高于3 200 m和3 800 m群体;4个群体均出现了高单倍型多样性、低核苷酸多样性的结果。高原林蛙遗传分化主要发生在群体间,中性检验和错配分析表明,高原林蛙群体可能没有经历扩张事件。cyt b基因在2 600 m、3 200 m和3 800 m群体都检测到了正选择位点。综上所述,2 000 m和2 600 m的高原林蛙群体遗传多样性高于3 200 m和3 800 m群体,4个海拔群体的遗传分化程度较高;cyt b基因可能对高原林蛙适应高海拔环境起到了积极作用。本研究可为理解高原林蛙适应高原环境及其保护提供参考...     

四川省若尔盖季节性水塘周边高原林蛙夏秋季活动特征

影响无尾两栖类活动的因素很多,水体是最主要的因素之一。本研究采用样线法,分别于2006年7月和9月下旬对若尔盖季节性水塘周边高原林蛙(Rana kukunoris)的活动特征进行了研究。样线宽2m,长70-150m,采用十字交叉法,基本按照东、南、西、北、东北、西北、东南、西南方向设置8条样线。结果表明:夏季高原林蛙主要在水塘周边活动,高原林蛙遇见率与水塘距离呈显著负相关(Pearson,成体:r=?0.479,P<0.05;亚成体:r=?0.480,P<0.05);90%的高原林蛙个体在距离水塘110m范围内活动,亚成体比成体更接近水体活动,远离水塘的成体选择泉眼和草沓草地活动。秋季高原林蛙的活动与水塘距离无显著相关性(Pearson,r=?0.016,P>0.05),水塘周边高原林蛙的遇见率很低,远离水塘的高原林蛙偏向选择泉眼活动。     

Distribution of N,P, K,Ca, Mg,S, Zn,Fe, Mn and Cu in groundnut

Summary Concentration of N, P, K, Ca, Mg and S in summer groundnut crop was higher than in kharif while Zn, Fe, Mn and Cu contents were higher in summer crop. Kernel's N, P and Zn; Leaflet's Ca and Mn; Stem's K and Fe; Root's S and Cu and Petiole's Mg contents were highest. Shell's N, P, K, Mg, S, Zn and Cu; Kernel's Ca, Fe and Mn contents were the least. N, P, K, S, Zn and Cu concentrations decreased linearly as the crop grew. Ca, Mg, Fe and Mn concentrations did not display any distinct pattern. Ca concentration was positively correlated with pod yield in both the seasons.     

Simultaneous measurement of the trace elements Al, As, B, Be, Cd, Co, Cu, Fe, Li, Mn, Mo, Ni, Rb, Se, Sr, and Zn in human serum and their reference ranges by ICP-MS

The goal of this article was to establish reference ranges of the concentration of trace elements in human serum and to compare these results with those reported by other authors. We describe the sample preparation and measurement conditions that allow the rapid, precise, and accurate determination of Al, As, B, Be, Cd, Co, Cu, Fe, Li, Mn, Mo, Ni, Rb, Se, Sr, and Zn in human serum samples (n=110) by inductively coupled plasma-mass spectrometry (ICP-MS). Accuracy and precision were determined by analyzing three reconstituted reference serum samples by comparison with other methods and by the standard addition procedure. The advantages of the ICP-MS method include short time of analysis of the elements mentioned, low detection limit, high precision, and high accuracy. Disadventages include a high risk of contamination due to the presence of some of the elements of interest in the environment, the relatively delicate sample handling, and the high cost of the equipment.     

Reference values for the concentrations of As,Cd, Co,Cr, Cu,Fe, I,Hg, Mn,Mo, Ni,Pb, Se,and Zn in selected human tissues and body fluids

This report attempts to formulate reference ranges of elemental concentrations for 15 trace elements in selected human tissues and body fluids. A set of samples consisting of whole blood, blood serum, urine, milk, liver, and hair were chosen and considered for 15 elements of biological significance: As, Cd, Co, Cr, Cu, F, Fe, I, Hg, Mn, Mo, Ni, Pb, Se, and Zn. The results represent wholly or partially data received from 40 countries of the global regions of Africa, Asia, Europe, North, South, and Central America, Australia, and New Zealand. This survey, even if qualitative, has been useful in demonstrating certain trends of trace-element scenarios around the world. It is of course recognized that both diet and environment exert a strong influence on the distribution pattern of several elements, such as As, Cd, Mn, Pb, Se, and Zn. A limited comparison of the available information on soil status of different countries reflected some interesting associations for elements, such as Mn and Zn. Importantly, this study revealed that only a few countries were in a position to identify a reasonable amount of data on samples requested for this project. Regretably, for a number of countries, any dependable data for even such essential elements as Cu, Fe, and Zn were not available. In view of the nutritional importance of many elements, the time is ripe for concerted efforts by intergovernmental agencies to initiate investigations or commission task forces/projects to generate reliable reference data for selected global regions, which sadly lack data of any kind at present.     

Crystal structure, detonation performance, and thermal stability of a new polynitro cage compound: 2, 4, 6, 8, 10, 12, 13, 14, 15-nonanitro-2, 4, 6, 8, 10, 12, 13, 14, 15-nonaazaheptacyclo [5.5.1.13, 11. 15, 9] pentadecane

A new polynitro cage compound 2, 4, 6, 8, 10, 12, 13, 14, 15-nonanitro-2, 4, 6, 8, 10, 12, 13, 14, 15-nonaazaheptcyclo [5.5.1.1(3,11).1(5,9)] pentadecane (NNNAHP) was designed in the present work. Its molecular structure was optimized at the B3LYP/6-31 G(d,p) level of density functional theory (DFT) and crystal structure was predicted using the Compass and Dreiding force fields and refined by DFT GGA-RPBE method. The obtained crystal structure of NNNAHP belongs to the P-1 space group and the lattice parameters are a = 9.99 ?, b = 10.78 ?, c = 9.99 ?, α = 90.01°, β = 120.01°, γ = 90.00°, and Z = 2, respectively. Based on the optimized crystal structure, the band gap, density of state, thermodynamic properties, infrared spectrum, strain energy, detonation characteristics, and thermal stability were predicted. Calculation results show that NNNAHP has detonation properties close to those of CL-20 and is a high energy density compound with moderate stability.     

Monovalent Cation Permeation through the Connexin40 Gap Junction Channel : Cs,Rb, K,Na, Li,TEA, TMA,TBA, and Effects of Anions Br,Cl, F,Acetate, Aspartate,Glutamate, and NO3

The unitary conductances and permeability sequences of the rat connexin40 (rCx40) gap junction channels to seven monovalent cations and anions were studied in rCx40-transfected neuroblastoma 2A (N2A) cell pairs using the dual whole cell recording technique. Chloride salt cation substitutions (115 mM principal salt) resulted in the following junctional maximal single channel current-voltage relationship slope conductances (γ_j in pS): CsCl (153), RbCl (148), KCl (142), NaCl (115), LiCl (86), TMACl (71), TEACl (63). Reversible block of the rCx40 channel was observed with TBA. Potassium anion salt γ_j are: Kglutamate (160), Kacetate (160), Kaspartate (158), KNO₃ (157), KF (148), KCl (142), and KBr (132). Ion selectivity was verified by measuring reversal potentials for current in rCx40 gap junction channels with asymmetric salt solutions in the two electrodes and using the Goldman-Hodgkin-Katz equation to calculate relative permeabilities. The permeabilities relative to Li⁺ are: Cs⁺ (1.38), Rb⁺ (1.32), K⁺ (1.31), Na⁺ (1.16), TMA⁺ (0.53), TEA⁺ (0.45), TBA⁺ (0.03), Cl⁻ (0.19), glutamate⁻ (0.04), and NO₃− (0.14), assuming that the monovalent anions permeate the channel by forming ion pairs with permeant monovalent cations within the pore thereby causing proportionate decreases in the channel conductance. This hypothesis can account for why the predicted increasing conductances with increasing ion mobilities in an essentially aqueous channel were not observed for anions in the rCx40 channel. The rCx40 effective channel radius is estimated to be 6.6 Å from a theoretical fit of the relationship of relative permeability and cation radius.     

Relations of the Al,B, Ba,Br, Ca,Cl, Cu,Fe, K,Li, Mg,Mn, Na,P, S,Si, Sr,and Zn mass fractions to morphometric parameters in pediatric and nonhyperplastic young adult prostate glands

The variation with age of the 18 trace element mass fractions and some histological characteristics of intact prostate glands of 50 subjects aged 0–30 years was investigated by instrumental neutron activation analysis, inductively coupled plasma atomic emission spectrometry, and a quantitative morphometric analysis. Mean values ± standard error of the mean (M ± SΕΜ) for the mass fractions (in milligrams per kilogram wet tissue) of these trace elements in pre-puberty were: Al 28.5 ± 9.0, B 0.40 ± 0.11, Ba 1.48 ± 0.44, Br 10.5 ± 1.5, Ca 241 ± 30, Cl 3,203 ± 278, Cu 3.51 ± 0.89, Fe 33.7 ± 4.1, K 2,364 ± 145, Li 0.020 ± 0.004, Mg 153 ± 23, Mn 0.46 ± 0.06, Na 2,286 ± 130, P 1,391 ± 100, S 1,698 ± 132, Si 62 ± 11, Sr 0.38 ± 0.08, and Zn 27.6 ± 2.3. During puberty and postpuberty, when there is a significant increase in circulating androgens, the mean values were: Al 7.2 ± 1.4, B 0.21 ± 0.05, Ba 0.25 ± 0.06, Br 5.8 ± 1.0, Ca 433 ± 81, Cl 2,314 ± 201, Cu 1.77 ± 0.13, Fe 20.9 ± 1.6, K 2,585 ± 118, Li 0.0088 ± 0.0014, Mg 232 ± 27, Mn 0.34 ± 0.04, Na 1,875 ± 107, P 1,403 ± 98, S 1,673 ± 73, Si 22.2 ± 3.1, Sr 0.22 ± 0.03, and Zn 93.3 ± 8.9. Mean values (M ± SΕΜ) of percent volumes (%) of the stroma, epithelium and lumen in the prostate before puberty were 73.4 ± 2.6, 20.4 ± 1.7, and 4.45 ± 0.94, respectively, versus 46.5 ± 2.5, 38.5 ± 1.9, and 14.9 ± 1.2 during puberty and postpuberty. This work’s results confirm that the Zn mass fraction in prostate tissue is an androgen-dependent parameter. For the first time it has been demonstrated that the glandular lumen is a main pool of Ca, Mg, and Zn accumulation and that the stroma is a main pool of Al, B, Ba, Br, Cl, Cu, Fe, Mn, Na, and Si accumulation in the normal human prostate, for the age range 0–30 years. It was concluded that the Ca, Mg, and Zn binds tightly within the prostatic fluid, because the volume of glandular lumen reflects the volume of prostatic fluid.     

Competitive inhibition and selectivity enhancement by Ca in the uptake of inorganic elements (Be, Na, Mg, K, Ca, Sc, Mn, Co, Zn, Se, Rb, Sr, Y, Zr, Ce, Pm, Gd, Hf) by carrot (Daucus carota cv. U.S. harumakigosun)

We investigated the uptake of inorganic elements (Be, Na, Mg, K, Ca, Sc, Mn, Co, Zn, Se, Rb, Sr, Y, Zr, Ce, Pm, Gd, and Hf) and the effect of Ca on their uptake in carrots (Daucus carota cv. U.S. harumakigosun) by the radioactive multitracer technique. The experimental results suggested that Na, Mg, K, and Rb competed for the functional groups outside the cells in roots with Ca but not for the transporter-binding sites on the plasma membrrane of the root cortex cells. In contrast, Y, Ce, Pm, and Gd competed with Ca for the transporters on the plasma membrane. The selectivity, which was defined as the value obtained by dividing the concentration ratio of an elemental pair, K/Na, Rb/Na, Be/Sr, and Mg/Sr, in the presence of 0.2 and 2 ppm Ca by that of the corresponding elemental pair in the absence of Ca in the solution was estimated. The selectivity of K and Rb in roots was increased in the presence of Ca. The selectivity of Be in roots was not affected, whereas the selectivity of Mg was increased by Ca. These observations suggest that the presence of Ca in the uptake solution enhances the selectivity in the uptake of metabolically important elements against unwanted elements.     

The Effect of Age and Gender on Al, B, Ba, Ca, Cu, Fe, K, Li, Mg, Mn, Na, P, S, Sr, V, and Zn Contents in Rib Bone of Healthy Humans

The effect of age and gender on major, minor, and trace element contents in the intact rib bone of 80 relatively healthy 15–55-year-old women and men was investigated. Contents or upper limit of contents of 16 chemical elements in the rib bone were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). Mean values (M?±?SΕΜ) for the mass fraction of Ba, Ca, Cu, Fe, K, Li, Mg, Na, P, S, Sr, and Zn (milligram per kilogram of dry bone) were as follows: 2.54?±?0.16, 171,400?±?4,050, 1.35?±?0.22, 140?±?11, 1,874?±?71, 0.049?±?0.011, 2,139?±?38, 5,378?±?88, 75,140?±?1,660, 1,881?±?51, 291?±?20, and 92.8?±?1.5, respectively. The upper limits of contents of Al, B, Mn, and V were <7.20, <0.65, <0.36, and <0.03, respectively. Statistically significant tendency for the Ca, Mg, and P content to decrease with age was found in the human rib bone, regardless of gender. The mass fraction of Fe in the male rib bone increases with age. It was shown that higher Ca, Mg, Na, P, and Sr mass fractions as well as lower Fe content were typical of female ribs as compared to those in male ribs.