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排序方式: 共有95条查询结果,搜索用时 250 毫秒
1.
Isao Sarashina Yoshiki Kunitomo Minoru Iijima Satoshi Chiba Kazuyoshi Endo 《Organic Geochemistry》2008,39(12):1742
Organic molecules such as proteins can be preserved in certain fossils. The bulk properties of fossil proteins of both vertebrates and invertebrates have been studied for over half a century. Named proteins have so far been identified, however, only in vertebrate fossils, such as collagen from mammoth bones. Using immunological assays, we examined 1500 year old fossils of the extinct land snail Mandarina luhuana from the Bonin islands for the presence of dermatopontin, a molluscan shell matrix protein. First, we examined the shell microstructure and mineralogy of the fossil shells using scanning electron microscopy (SEM) and powder X-ray diffraction (XRD) in order to estimate the extent of diagenetic alteration. The results suggest that the original microstructure and mineralogy of the shells are preserved. Antiserum raised against the Type-1 dermatopontin fragment of the living land snail Euhadra brandtii showed significant immunological reactivity with the extracts from the fossil shells of M. luhuana. Immunological binding curves drawn for the shell extracts of extant M. aureola and the extinct M. luhuana confirmed the presence of dermatopontin in the fossil shells and provided an estimate that about 75–98% of the original dermatopontin was lost from the M. luhuana fossils. This is the first report of a named protein being identified in invertebrate fossils. 相似文献
2.
Standing stocks and production rates of phytoplankton and planktonic copepods in the Inland Sea of Japan 总被引:1,自引:0,他引:1
Standing stocks and production rates of phytoplankton and planktonic copepods were investigated at 15 stations in the Inland Sea of Japan during four cruises in October–November 1979, January, April and June 1980. The overall mean of phytoplankton biomass was relatively constant during the study period, ranging from 2.3 mg chl.a m–3 in April to 3.6 mg chl.a m–3 in October–November. Primary production was low in January (mean: 90 mg C m–2 d–1), but higher than 375 mg C m–2 d–1 on the other occasions. Integrated annual primary production was 122 g C m–2 yr–1. In terms of carbon weight,Paracalanus parvus was the most important copepod species. The variation of the mean copepod biomass (range: 7.6 mg C m–3 in April to 20.2 mg C m–3 in June) was smaller than that of copepod production, which was estimated by the Ikeda-Motoda's physiological method. Copepod producion was low in cold seasons (0.6 and 0.9 mg C m–3 d–1 in January and April, respectively), and increased, following the elevation of primary production, to 4.9 mg C m–3 d–1 in June. Annual copepod production was 33.7 g C m–2 yr–1, of which herbivore (secondary) production was 26.4 g C m–2 yr–1 (21.7% of primary production). The ratios of pelagic planktivorous fish catch and total fish catch to the primary production were 0.82 and 1.8%, respectively, indicating very high efficiency in exploiting fishery resources in the Inland Sea of Japan. 相似文献
3.
Michiaki Sugita Tetsuya Hiyama Nobuhiko Endo Shao-Fen Tian 《Boundary-Layer Meteorology》1995,73(1-2):145-158
Careful micrometeorological measurements on an empty parking lot allowed determination of the surface fluxes of sensible heatH and of momentum by applying profile equations derived from Monin-Obukhov similarity theory with two sets of the stability correction function for momentum
m
and sensible heat
h
. These fluxes were compared with reference values ofH independently determined by means of an eddy correlation technique. In general, better agreement was found betweenH values derived from profiles with the stability functions of Brutsaert (1992) and referenceH values, than when the Businger-Dyer functions were used to deriveH. The disagreement in the latter comparison was especially serious under strongly unstable conditions, with the value ofy=–z/L (wherez is the height andL is the Obukhov length) larger than 10. A closer look at the procedure for calculatingH from the profiles revealed that the large differences between theH values derived with these two different versions of the stability correction functions were caused by the small differences of the
h
values, and not by the larger differences of the
m
values. This result stems from the strong sensitivity of the resultingH values on the choice of
h
. 相似文献
4.
Katsuhiro Tsukimura Hiromoto Nakazawa Tadashi Endo Osamu Fukunaga 《Physics and Chemistry of Minerals》1992,19(4):203-212
This paper describes the distribution of Fe and Ni between the octahedral and tetrahedral sites in pentlandite (Fe,Ni)9S8. The dependence of the distribution on pressure and temperature and the activation energy of the cation exchange reaction were determined through annealing experiments. Synthetic crystals were annealed at 433–723 K and pressures up to 4 GPa, and natural crystals were annealed at 423, 448 and 473 K in evacuated silica capillary tubes for various durations. The cation distributions in the synthetic crystals were determined with an X-ray powder method employing the anomalous dispersion effect of CuK. and FeK radiations, while those of natural crystals were calculated from the cell dimensions. The values of U, S and V for the Fe/Ni exchange reaction are –6818 J mol–1, 20.52 J K–1 mol–1, and 6.99 × 10–6 m3 mol–1, respectively. The dependence of the Fe/Ni distribution on pressure (Pa) and temperature (Kelvin) was determined as lnK = 2.47+8.20 × 102
T
–1+8.41 x 10–7
T
–1
P, where K = (Fe/Ni)octahedral /(Fe/Ni)tetrahedral. The activation energy of the cation exchange reaction was 185 kJ mol–1. 相似文献
5.
Andrew N. Ostrovsky Reishi Takashima Matthew H. Dick Andrei V. Grischenko Hiroshi Nishi Shunsuke F. Mawatari 《Cretaceous Research》2006,27(6):859-862
A small collection of recrystallised, encrusting colonies of a single species from the Mikasa Formation (lower Middle Cenomanian), represents the first record of cheilostome (malacostegan or anascan) bryozoans from Hokkaido, Japan. 相似文献
6.
Hiroshi Kobayashi Keiichi Tamura Shunsuke Tanimoto 《Soil Dynamics and Earthquake Engineering》2002,22(9-12):1135-1141
In order to improve seismic design technology of bridges, it is necessary to evaluate the vibration characteristics of a bridge–soil system that consists of soil, foundation structure, pier and superstructure. However, there have been few experimental studies on seismic behavior of bridge–soil system. In this paper, we conducted the hybrid vibration experiment on seismic behavior of bridge–soil system, and examined the applicability of hybrid vibration experiment to study seismic response of bridge–soil system. Based on the experiment results, seismic response of bridge was quantitatively studied. 相似文献
7.
Migration characteristics of dense non-aqueous phase liquids (DNAPLs) in the subsurface can be expressed as a water–DNAPL two-phase system based on mainly the k–S–p relations, which describe the relations among relative permeability (k), degree of water saturation (S), and capillary pressure head (p). The aims of this research are to develop an experimental system with new type of probes, such as the electrical conductivity probe for measuring the degree of water saturation and the hydrophilic and hydrophobic tensiometer for measuring the pore water and DNAPL pressures, and also to estimate the results obtained from the developed experimental system. From these tests, the excellent k–S–p relations were obtained and the efficiency and validity of this developed experimental system have been confirmed in terms of the concept of the scaling coefficient calculated by interfacial tensions. 相似文献
8.
GPS Solutions - Recently, 3D building models have become an important aid to many positioning methods such as LiDAR and GPS positioning. Creating an accurate 3D building model requires accurate 2D... 相似文献
9.
近200年来黑河下游天鹅湖湖泊沉积记录的环境变迁 总被引:14,自引:2,他引:12
根据2002-2004年洞庭湖水质监测数据,参照GB3838-2002中Ⅲ类水质标准,选用内梅罗水污染指数法和黄浦江污染指数对洞庭湖水质现状进行评价,结果表明:(1)洞庭湖水体的主要污染指标是总磷,总氮和粪大肠菌群;(2)黄浦江污染指数平均值为0.27,所以洞庭湖12个断面水质无黑臭现象发生;(3)枯水期西洞庭湖和南洞庭湖水质污染最严重,平水期西洞庭湖水质污染最严重,洞庭湖丰水期的污染程度小于平水期;(4)洞庭湖的大部分水体的水质主要处于轻度污染的状态,局部水体的水质在枯水期达到重污染的状态. 相似文献
10.
Petrogenesis and implications of jadeite‐bearing kyanite eclogite from the Sanbagawa belt (SW Japan)
Jadeite‐bearing kyanite eclogite has been discovered in the Iratsu body of the Sanbagawa belt, SW Japan. The jadeite + kyanite assemblage is stable at higher pressure–temperature (P–T) conditions or lower H2O activity [a(H2O)] than paragonite, although paragonite‐bearing eclogite is common in the Sanbagawa belt. The newly discovered eclogite is a massive metagabbro with the peak‐P assemblage garnet + omphacite + jadeite + kyanite + phengite + quartz + rutile. Impure jadeite is exclusively present as inclusions in garnet. The compositional gap between the coexisting omphacite (P2/n) and impure jadeite (C2/c) suggests relatively low metamorphic temperatures of 510–620 °C. Multi‐equilibrium thermobarometry for the assemblage garnet + omphacite + kyanite + phengite + quartz gives peak‐P conditions of ~2.5 GPa, 570 °C. Crystallization of jadeite in the metagabbro is attributed to Na‐ and Al‐rich effective bulk composition due to the persistence of relict Ca‐rich clinopyroxene at the peak‐P stage. By subtracting relict clinopyroxene from the whole‐rock composition, pseudosection modelling satisfactorily reproduces the observed jadeite‐bearing assemblage and mineral compositions at ~2.4–2.5 GPa, 570–610 °C and a(H2O) >0.6. The relatively high pressure conditions derived from the jadeite‐bearing kyanite eclogite are further supported by high residual pressures of quartz inclusions in garnet. The maximum depth of exhumation in the Sanbagawa belt (~80 km) suggests decoupling of the slab–mantle wedge interface at this depth. 相似文献