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101.
This paper presents the results of the determination of several trace elements (total and organic mercury, selenium, cadmium, lead, copper, manganese and zinc) in six species of marine organisms (Nephrops norvegicus, Engraulis encrasicolus, Mullus barbatus, Mullus surmuletus, Merluccius merluccius, and Sarda sarda), sampled in the Ligurian Sea (North-West Mediterranean) during a three-year period, from 1998 to 2000. The species analysed (388 samples) are the same studied in previous investigations in the same area (260 samples), so that a comparison with previous data measured in 1977-1986 was possible, in order to evaluate the variation of the marine environment in that area with respect to that period. Biological parameters of the specimens (length and weight of the individuals, and also sex for N. norvegicus) were taken into account in order to make possible the comparison between old and new data. No appreciable variation occurred in the levels of the trace elements analysed during the period 1998-2000, while the comparison with the data collected about 25 years ago showed a decrease of all the elements except for selenium. 相似文献
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103.
Zegers RG van Den Berg AM Brandenburg S Fleurot FR Fujiwara M Guillot J Hannen VM Harakeh MN Laurent H van Der Schaaf K van Der Werf SY Willis A Wilschut HW 《Physical review letters》2000,84(17):3779-3782
The (nat)Pb(3He,tp) reaction at E(3He) = 177 MeV was studied to identify 2Planck's over 2piomega isovector monopole strength in Bi isotopes. Monopole strength was found in the region -45
相似文献
104.
An analogy is stressed between the order-parameter symmetries of the two-dimensional d-pairing wave superconductors and of liquid-crystal mesophases formed from achiral bent-shaped molecules. It leads to a definition of a class of liquid-crystal states which are the analogs of the unconventional superconducting states, and are characterized by a loss of discrete symmetry operations of the parent state. 相似文献
105.
Background
Neurons require an elaborate system of intracellular transport to distribute cargo throughout axonal and dendritic projections. Active anterograde and retrograde transport of mitochondria serves in local energy distribution, but at the same time also requires input of ATP. Here we studied whether brain-type creatine kinase (CK-B), a key enzyme for high-energy phosphoryl transfer between ATP and CrP in brain, has an intermediary role in the reciprocal coordination between mitochondrial motility and energy distribution. Therefore, we analysed the impact of brain-type creatine kinase (CK-B) deficiency on transport activity and velocity of mitochondria in primary murine neurons and made a comparison to the fate of amyloid precursor protein (APP) cargo in these cells, using live cell imaging. 相似文献106.
van Der Lee AM van Druten NJ van Exter MP Woerdman JP Poizat JP Grangier P 《Physical review letters》2000,85(22):4711-4714
We investigate the impact of the Petermann-excess-noise factor K>/=1 on the possibility of intensity noise squeezing of laser light below the standard quantum limit. Using an N-mode model, we show that squeezing is limited to a floor level of 2(K-1) times the shot noise limit. Thus, even a modest Petermann factor significantly impedes squeezing, which becomes impossible when K>/=1.5. This appears as a serious limitation for obtaining sub-shot-noise light from practical semiconductor lasers. We present experimental evidence for our theory. 相似文献
107.