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Under artificial LD cycles(6,12,18 L),the elvers of Japanese eel,Anguilla japonica,showed a 24 h cycle of locomotor activity rhythm being most active at light transitions:the eels' activity rose to a primary peak after lights-off,followed by a quiescent period during which they buried into the shelters or lying motionlessly on sand for most of the time,and then reached a secondary peak before lights-on.Elvers could resynchronize their activity rhythm with a new photo cycle within 4 d.Moreover,their activity level at dark phase significantly increased as the light period was prolonged:higher activity levels during shorter dark period.However,the elvers did not display clearly the existence of a circadian rhythm under constant light or dark conditions.The timing of daily activity rhythm evidenced in the Japanese eels may occur through the action of the LD cycles with a weak participation of an endogenous circadian system.In all the LD cycles,over 99% of the activity occurred in the dark phase,indicating that the eels were always nocturnally active no matter what time of day it might be.Under 12 L conditions,the eels' activity level and the time outside sand were significantly elevated both at light and dark phases as temperature increased from 10~15 to 20~25 ℃.The activity rhythm pattern(i.e.,two peaks occurring around light transitions) did not apparently change among temperatures.However,in contrast with the primary activity peaks immediately after lights-off at 20 and 25 ℃,the timing of the primary peaks at 10 and 15 ℃ showed a latency of a few hours following lights-off,indicating the inhibiting effect of low temperature on the eels' activity. 相似文献
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We measured the ammonium excretion, phosphate excretion and respiration rates of the scyphomedusa Aurelia aurita from Ondo Strait, in the central part of the Inland Sea of Japan, at 28 and 20°C. The rates measured at 28°C were converted
to those at 20°C using the Q10 values, i.e. 1.56, 1.57 and 2.80, for ammonium excretion, phosphate excretion and respiration rates, respectively. The composite
relationships between metabolic rates and wet weight of a medusa (WW, g, range 11–1330 g) at 20°C were expressed by the following allometric equations. For ammonium excretion rate (N, μmoles N medusa−1d−1): N = 0.497WW
1.09, phosphate excretion rate (P, μmoles P medusa−1d−1): P = 0.453WW
0.84, and respiration rate (R, μmoles O2 medusa−1d−1): R = 96.9WW
1.06. Mean O:N ratios (i.e. atomic ratios of 16.9 and 11.0 at 28 and 20°C, respectively) indicated that the metabolism of A. aurita medusae was protein-dominated. These metabolic parameters enabled us to estimate the nitrogen and phosphorus regeneration
rates of an A. aurita medusa population typical of early summer in the Ondo Strait (means of water temperature, medusa individual weight and population
biomass: 20°C, 200 g WW and 50.8 g WW m−3, respectively). Regenerated nitrogen and phosphorus were equivalent to 10.0 and 21.6% of phytoplankton uptake rates, respectively,
nearly twice that estimated for mesozooplankton, demonstrating that A. aurita medusae are key components of the plankton community, influencing the trophic and nutrient dynamics in the Ondo Strait during
early summer. 相似文献
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In order to understand the processes of land surface-atmosphere interaction over de-sertification area, it is indispensable to utilize of satellite remote sensing. Two scenes of LandsatTM were used to produce a set of maps of surface reflectance, MSAVI, vegetation coverage, sur-face temperature, net radiation, soil heat flux, sensible heat flux and latent heat flux. Statisticalanalysis based on these maps revealed some quantitative significant land surface characteristics.Future developments of the method are also discussed. 相似文献
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基于多测点 LA-ICPMS 的耳石核区元素指纹分析技术及其在鱼类群体识别中的实证研究 总被引：3，自引：0，他引：3
构建了多测点激光剥蚀取样(LA)-ICPMS 元素分析-剥蚀点显微结构验证的耳石核区元素指纹分析技术, 以此进行了五个刀鲚群体(辽东湾、渤海湾、黄河口、胶州湾及长江口群体)识别的实证研究。 结果发现, 耳石核区 Sr : Ca 和 Ba : Ca 比值是有效识别各地理群体的元素指纹, 基于二者的各群体判别成功率在 46.2%—92.3%之间, 总体判别成功率为 72.7%, 表现出其较强的群体识别能力。借助于耳石内的放射状标志带结构特征可较准确地识别耳石核区, 保证了激光剥蚀点的精准定位及剥蚀取样的质量和代表性; 对激光剥蚀点的显微结构验证可以消除无效剥蚀点的元素测定数据对元素指纹分析产生的误差; 刀鲚的定居性、溯河性等生活特性降低了各群体混合几率和环境因素对耳石核区微化学组成的影响, 使得耳石核区元素指纹具备高稳定性和特质性。这些研究技术的改进和刀鲚的生理生态特性提高了该技术识别各地理群体的准确性和效率。 相似文献
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Yuki KIMURA Joseph A. NUTH III Katsuo TSUKAMOTO Chihiro KAITO 《Meteoritics & planetary science》2011,46(1):92-102
Abstract– Exothermic reactions during the annealing of laboratory synthesized amorphous magnesium‐bearing silicate particles used as grain analogs of cosmic dust were detected by differential scanning calorimetry (DSC) in air. With infrared spectroscopy and transmission electron microscopy, we show that cosmic dust could possibly undergo fusion to larger particles, with oxidation of magnesium silicide and crystallization of forsterite as exothermic reactions in the early solar system. The reactions begin at approximately 425, approximately 625, and approximately 1000 K, respectively, and the reaction energies (enthalpies) are at least 727, 4151, and 160.22 J g−1, respectively. During the crystallization of forsterite particles, the spectral evolution of the 10 μm feature from amorphous to crystalline was observed to begin at lower temperature than the crystallization temperature of 1003 K. During spectral evolution at lower temperature, nucleation and/or the formation of nanocrystallites of forsterite at the surface of the grain analogs was observed. 相似文献
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Yoshihiro Yokoyama Hiroshi Tsukamoto Tohru Suzuki Shohshi Mizuta Reiji Yoshinaka 《中国海洋大学学报(英文版)》2005,4(3):214-218
In this study, genes of two distinct tissue inhibitors of metalloproteinases-2 （TIMP-2） from Japanese puffer fish Fugu rubripes, Fugu TIMP-2a and TIMP-2b, were cloned. The open reading frames of Fugu TIMP-2a and TIMP-2b cDNAs are composed of 660 and 657 nucleotides and 220 and 219 amino acids, respectively. Both Fugu TIMP-2s contain 12 cysteine residues, which might form six disulfide bonds as in other animals＇ TIMP-2s. Reverse-transcribed polymerase chain reaction analysis showed the mRNAs of Fugu TIMP-2a and TIMP-2b to be expressed in some tissues examined with different expression patterns. These findings suggest that the two distinct Fugu TIMP-2s might perform different functions in Fugu tissues. 相似文献
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Jun‐ichi MATSUDA Hidetomo TSUKAMOTO Chie MIYAKAWA Sachiko AMARI 《Meteoritics & planetary science》2010,45(3):361-372
Abstract– We have determined the elemental abundances and the isotopic compositions of noble gases in a bulk sample and an HF/HCl residue of the Saratov (L4) chondrite using stepwise heating. The Ar, Kr, and Xe concentrations in the HF/HCl residue are two orders of magnitude higher than those in the bulk sample, while He and Ne concentrations from both are comparable. The residue contains only a portion of the trapped heavy noble gases in Saratov; 40 ± 9% for 36Ar, 58 ± 12% for 84Kr, and 48 ± 10% for 132Xe, respectively. The heavy noble gas elemental pattern in the dissolved fraction is similar to that in the residue but has high release temperatures. Xenon isotopic ratios of the HF/HCl residue indicate that there is no Xe‐HL in Saratov, but Ne isotopic ratios in the HF/HCl residue lie on a straight line connecting the cosmogenic component and a composition between Ne‐Q and Ne‐HL. This implies that the Ne isotopic composition of Q has been changed by incorporating Ne‐HL (Huss et al. 1996) or by being mass fractionated during the thermal metamorphism. However, it is most likely that the Ne‐Q in Saratov is intrinsically different from this component in other meteorites. The evidence of this is a lack of correlation between the isotopic ratio of Ne‐Q and petrologic types of meteorites (Busemann et al. 2000). A neutron capture effect was observed in the Kr isotopes, and this process also affected the 128Xe/132Xe ratio. The 3He and 21Ne exposure ages for the bulk sample are 33 and 35 Ma, respectively. 相似文献
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