Absence of cooling in New Zealand and the adjacent ocean during the Younger Dryas chronozone

As the climate warmed at the end of the last glacial period, a rapid reversal in temperature, the Younger Dryas (YD) event, briefly returned much of the North Atlantic region to near full-glacial conditions. The event was associated with climate reversals in many other areas of the Northern Hemisphere and also with warming over and near Antarctica. However, the expression of the YD in the mid- to low latitudes of the Southern Hemisphere (and the southwest Pacific region in particular) is much more controversial. Here we show that the Waiho Loop advance of the Franz Josef Glacier in New Zealand was not a YD event, as previously thought, and that the adjacent ocean warmed throughout the YD.     

A significant upward shift in plant species optimum elevation during the 20th century

Spatial fingerprints of climate change on biotic communities are usually associated with changes in the distribution of species at their latitudinal or altitudinal extremes. By comparing the altitudinal distribution of 171 forest plant species between 1905 and 1985 and 1986 and 2005 along the entire elevation range (0 to 2600 meters above sea level) in west Europe, we show that climate warming has resulted in a significant upward shift in species optimum elevation averaging 29 meters per decade. The shift is larger for species restricted to mountain habitats and for grassy species, which are characterized by faster population turnover. Our study shows that climate change affects the spatial core of the distributional range of plant species, in addition to their distributional margins, as previously reported.     

Formation of regulatory patterns during signal propagation in a Mammalian cellular network

We developed a model of 545 components (nodes) and 1259 interactions representing signaling pathways and cellular machines in the hippocampal CA1 neuron. Using graph theory methods, we analyzed ligand-induced signal flow through the system. Specification of input and output nodes allowed us to identify functional modules. Networking resulted in the emergence of regulatory motifs, such as positive and negative feedback and feedforward loops, that process information. Key regulators of plasticity were highly connected nodes required for the formation of regulatory motifs, indicating the potential importance of such motifs in determining cellular choices between homeostasis and plasticity.     

魔芋贮藏期失水率研究

魔芋在采收后除了商品芋立即出售外,留作种芋的都要贮藏4～5个月,在此期间,魔芋的水分逐步挥发,失水率与时间成正比关系,且失水率的高低与种芋的大小关系密切,种芋越小失水率越低,种芋越大失水率越高,贮藏5个月后,失水率均达20.0%以上。     

Measurement of regional blood flow by indicator dilution

Appropriate selection of injection and collection sites permits quantification of certain regional blood flows by the single-injection, indicator-dilution method. Quantifying formulas are derived, and application of the method to several regional beds is described.     

Isotope dilution method for assay of inagglutinable erythrocytes

The number of cells that remain free in the presence of agglutinin is usually much larger than the number of inagglutinable cells. The true inagglutinable proportion can be found by successive agglutinations of a labeled population in the presence of unlabeled carrier cells. By this means it is shown that group A persons possess non-A erythrocytes in proportions of the order of 10(-3).     

论奥林匹克语境下武术话语权力的缺失

以符号学与福柯的话语权力理论为基础,分析了“北京2008武术比赛”在奥林匹克语境中的意义,并以文化差异为出发点,对武术在奥林匹克语境下话语权缺失的原因及其机制进行了分析,最后提出了中国武术构建自我话语权力体系的策略。     

Comment on "Absence of cooling in New Zealand and the adjacent ocean during the Younger Dryas chronozone"

Barrows et al. (Reports, 5 October 2007, p. 86) presented cosmogenic exposure dates and data from an ocean sediment core that challenge evidence for glacier advance in New Zealand during the Younger Dryas event. We use modeling of geomorphic processes to argue that their cosmogenic exposure dates are inconclusive.     

Absence of Short-Term Variability of CTA 102

Short-time variations in intensity of about 40 percent, with a period of the order of 100 days, have been reported for the quasistellar radio source CTA 102 at 32.5-centimeter wavelength. We have observed CTA 102 at 25.5-centimeter wavelength over a 67-day, period and have detected no significant variations of intensity.     

渗渠取水压力变化过程分析

针对渗渠取水过程中的压力变化以及由此引起的渗渠取水量变化,结合模型试验,运用源汇理论建立了流体力学方程。阐述了点汇是导致渗渠取水过程中压力降落的原因,而压力的减小导致渗渠取水量的降低,取水量的降低又会使得补给水头增大,缓解了因点汇形成的压力降落,这是一个动态过程。试验结果表明,渗渠运行170~250 min后达到压力平衡位置,处于稳定取水状态,且管径越大稳定用时越长,非完整式渗渠较完整式渗渠稳定用时更长。     

土壤冻结条件下水、热耦合运移数值模拟研究

根据冻结条件下非饱和土壤水分运动和热量迁移的基本方程,推求冻土水热耦合迁移的数学模型,采用Grank—Nicolson计算格式及迭代方法进行求解。通过计算与实验结果对比,表明采用的数学模型和数值计算方法可靠,为模拟各种不同条件下的土壤冻结过程创造了条件。     

Absence of microorganisms in crustacean digestive tracts

Two marine and one terrestrial wood-boring isopod species and one wood-inhabiting amphipod species maintain a digestive tract free of microorganisms. Digestive tracts examined in toto with the scanning electron microscope were devoid of microorganisms. In contrast, the outer exoskeleton surfaces of these crustaceans support a dense bacterialflora. Observations of the hindgut of termites revealed a diverse gut microflora as expected.     

Absence of neutral alkali atoms in rhodizite

The formula CsB(l2)Be(4)Al(4)O(28) has been proposed by others for the mineral rhodizite. Electron-spin-resonance and magnetic susceptibility measurements prove the absence of neutral cesium atoms. An ionic formula CsB(11)Be(4)Al(4)O(26)(OH)(2) is proposed.     

Absence of REM rebound after barbiturate withdrawal

Administration of three different barbiturates reduced rapid eye movement (REM) sleep. Drug withdrawal led to a return to baseline REM] values without significant overshoot. Similar results are observed with administration of benzodiazepines in pharmacologically equivalent dosages; therefore, a distinction between these two drug classes on the basis of withdrawal effects on the sleep electroencephalogram appears unwarranted. Further investigation is required determine why high REM levels are sometimes associated with the withdrawal of sedative-hypnotic agents.     

Reactivity of the gold/water interface during selective oxidation catalysis

The selective oxidation of alcohols in aqueous phase over supported metal catalysts is facilitated by high-pH conditions. We have studied the mechanism of ethanol and glycerol oxidation to acids over various supported gold and platinum catalysts. Labeling experiments with (18)O(2) and H(2)(18)O demonstrate that oxygen atoms originating from hydroxide ions instead of molecular oxygen are incorporated into the alcohol during the oxidation reaction. Density functional theory calculations suggest that the reaction path involves both solution-mediated and metal-catalyzed elementary steps. Molecular oxygen is proposed to participate in the catalytic cycle not by dissociation to atomic oxygen but by regenerating hydroxide ions formed via the catalytic decomposition of a peroxide intermediate.     

利用LF-NMR技术研究鹰嘴蜜桃在贮藏过程中水分的变化

利用低场核磁共振技术确立了鹰嘴蜜桃在贮藏过程中水分的总信号幅度和含水率的关系为y=1.280 8x-12.17(R~2=0.982 6).随着时间推移,鹰嘴蜜桃的3种水分含量均减少,其中自由水的减少幅度最大,不易流动水次之,结合水最小.另外,3种水分的流动性均减弱,结合水减弱程度最大,不易流动水次之,自由水最小.鹰嘴蜜桃的3种水分的变化以及总的水分含量与其呼吸强度和硬度有一定关联.呼吸强度的增强伴随着含水量的减少,硬度与水分含量呈显著正相关.     

Firing patterns of hypothalamic supraoptic neurons during water deprivation in monkeys

Water deprivation in monkeys caused an acceleration of action potential firing of supraoptic neurons, but not of neurons located 2 to 3 millimeters above the hypothalamic supraoptic nucleus. Whereas in the normally hydrated animal only 12 percent of the neuroendocrine cells discharged periodically, the proportion of these periodic bursters increased markedly with increasing plasma osmolarity. This finding suggests that such periodically firing supraoptic neurons are those engaged in active neurohypophyseal hormone secretion.     

中国民族特色药材艾纳香研究进展

\t\t\t\t\t目的\t\t\t\t\t了解特色药用植物艾纳香(Blumea balsamifera L. DC.)幼苗期在不同水分胁迫下不同取样时期的苗高、地径、生物量及叶结构变化,寻找最佳栽培条件。\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t方法\t\t\t\t\t2014年5—9月,以一年生艾纳香幼苗为试验材料,进行不同程度(土壤田间持水量：CK为80%,轻度胁迫LD为60%,中度胁迫MD为40%,重度胁迫SD为30%)的干旱胁迫盆栽试验,测定艾纳香生物量和显微镜下的叶结构指标,分析不同程度干旱对艾纳香生物量和叶片结构的影响。\t\t\t\t\t\t\t\t\t\t\t\t\t结果\t\t\t\t\t不同干旱程度下,艾纳香的生物量、叶片厚度、栅栏组织与细胞结构紧密度(CTR)均随土壤水分的减少而减少,而根冠比、细胞结构疏松度(SR)与海绵组织随水分的减少而增大。\t\t\t\t\t\t\t\t\t\t\t\t\t结论\t\t\t\t\t中度胁迫是艾纳香生长可承受的最大范围,人工种植在土壤含水量40%下能维持叶片与地径的生长,从而获得药用材料。\t\t\t\t