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1.
2.
The fully enclosed Taiaro lagoon is hypersaline (42.5 psu) and non-tidal; constant salinity and water level result from strong
evaporation balanced by low percolation through the lagoon floor. Seawater can flow over the atoll rim during exceptionally
high seas and may then replenish lagoonal communities with propagules of oceanic origin. The distinctive water chemistry of
the lagoon suggests a possible way of identifying these immigrants. We established this potential by analysing stable isotopes
of carbon and oxygen in the recent growth layers of otoliths of two adult reef fishes, Chaetodon ulietensis and Acanthurus triostegus, collected from both sides of the atoll rim. Fish from the two locations were discriminated by their isotopic signatures,
suggesting that analysis of the microchemical signatures deposited during the larval development could be used in future work
to determine which individuals and species complete their life-cycles in this unusual lagoon.
Accepted: 28 August 1997 相似文献
3.
The association between the red macroalga Jania adhaerens J. V. Lamour. and the sponge Haliclona caerulea is the most successful life‐form between 2 and 4 m depth in Mazatlán Bay (Mexican Pacific). J. adhaerens colonizes the rocky intertidal area and penetrates into deeper areas only when it lives in association with H. caerulea. The aposymbiotic form of the sponge has not been reported in the bay. To understand the ecological success of this association, we examined the capacity of J. adhaerens to acclimate in Mazatlán Bay using transplant experiments. The transplanted aposymbiotic J. adhaerens did not survive the first 2 weeks; however, J. adhaerens when living in association with H. caerulea, acclimated easily to depth, showing no sign of mortality during the 103 d of the experiment. We conclude that the ability of J. adhaerens to colonize in deeper areas in this hydrodynamic environment may in part rely on the protection provided by the sponge to the algal canopy. Both species contribute to the shape of the associated form. Nevertheless, the morphological variation in the association appears to be dominated by the variation in J. adhaerens canopy to regulate pigment self‐shading under light‐limited conditions and/or tissue resistance under high hydrodynamics. Consequently, our results are consistent with light as the abiotic controlling factor, which regulates the lower depth distribution of the association in Mazatlán Bay, through limiting the growth rate of J. adhaerens. Hydrodynamics may determine the upper limit of the association by imposing high mass losses. 相似文献
4.
Peter Lewis 《Journal of bioethical inquiry》2007,4(1):51-55
The display of personal photographs in hospital is a common practice that has yet to be rigorously examined. The photographs
displayed are subject to interpretation by the viewer and may lead to misunderstandings or miscommunication if clarification
of meaning is not sought. This paper explores a range of possible meanings that the display of photographs in hospital may
hold, based on a case study of a 15 year old boy hospitalised with a life threatening illness. Further research is needed
into the actual meanings attributed to the display of photographs in hospital by patients and family members. 相似文献
5.
Kristina M. Obom Andrew Magno Patrick J. Cummings 《Journal of visualized experiments : JoVE》2013,(79)
Fermentation systems are used to provide an optimal growth environment for many different types of cell cultures. The ability afforded by fermentors to carefully control temperature, pH, and dissolved oxygen concentrations in particular makes them essential to efficient large scale growth and expression of fermentation products. This video will briefly describe the advantages of the fermentor over the shake flask. It will also identify key components of a typical benchtop fermentation system and give basic instruction on setup of the vessel and calibration of its probes. The viewer will be familiarized with the sterilization process and shown how to inoculate the growth medium in the vessel with culture. Basic concepts of operation, sampling, and harvesting will also be demonstrated. Simple data analysis and system cleanup will also be discussed. 相似文献
6.
Abstract. Gas exchange, leaf-nitrogen concentration and water potential were measured in early and late spring in early successional herbaceous plants occurring after cutting and after fire, and in mature woody species from the Mediterranean climax community Quercetum ilicis in central Italy. Net photosynthesis peaked in early spring in all species studied when values for temperature and light were lower but leaf-nitrogen content was higher as compared to late spring, suggesting that nitrogen more than energy input controlled photosynt-hetic rates. Herbaceous pioneer species occurring after cutting showed higher field photo synthetic capacity than evergreen climax trees and shrubs. By contrast, net photosynthesis of herbaceous species occurring in a persistent stage after fire, was in the same range as that of climax trees. This evidence suggests that carbon-gaining appears to be partly related to the dynamic stage of succession and not solely to the growth form. 相似文献
7.
MICHAEL D. BAKER CHARLES R. VOSSBRINCK JAMES J. BECNEL JOSEPH V. MADDOX 《The Journal of eukaryotic microbiology》1997,44(3):220-225
ABSTRACT. Sequences of the small subunit rRNA genes of Amblyospora californica and an Amblyospora sp. from Culex salinarius were determined. These sequences were compared phylogenetically with 16 other microsporidia. The results suggest Amblyospora forms a sister taxon to the rest of the microsporidia examined. The basal position of Amblyospora is discussed with respect to the evolution of microsporidian life cycles. These sequences represent the longest microsporidian small subunit rRNA genes sequenced to date, 1,359 and 1,358 bp, respectively. Structural features and GC content (49% for both) are comparable to those of other microsporidia which have been sequenced. 相似文献
8.
The Yanomama Indians of Southern Vanezuela and Northern Brazil are one of the largest, relatively unacculturated tribes of the tropical rain forest. Over a period of eight years data have been collected from a considerable portion of their territory on estimated age, sex ratio, fertility rates (as determined by physical examination and urine tests), and infant death rates. Although it has been impossible to collect direct data on infanticide, this subject can be approached indirectly through distortions of the sex ratio and anecdotal information. Some historical data are also available as a basis for estimating tribal expansion in the past 100 years. With this material it has been possible to construct Life Tables for the Yanomama, and to explore the results of various perturbations of the input parameters. Data are also presented on patterns of mating and reproduction: number of spouses, mean and variance in number of surviving children, frequency of “extra-marital conceptions” based on the results of extensive blood group typings, and consanguinity rates as determined by observation and computer simulation. Although we do not present the Yanomama as typical, these data are seen as providing a basis for more realistic population models than have existed in the past. In addition, the data provide a basis for relatively precise estimates of such demographic measures as Fisher's Reproductive Value, Crow's Index of Total Selection, and Weiss' Index of Growth Regulation. 相似文献
9.
Isolde Hagemann 《Plant Systematics and Evolution》1987,155(1-4):165-187
The morphology, altitudinal distribution and phytocoenology ofHypericum empetrifolium
Willd., var.oliganthum
Rech. fil. and var.tortuosum
Rech. fil. are reassessed and as a result, the taxa are treated at subspecific rank. Essential characters proved to be growth form, number of flowers, foliage and epidermal surface characters, shape of seeds and testa sculpturing.The different growth forms can be interpreted as adaptations to the local habitats.Hypericum empetrifolium
Willd. subsp.empetrifolium is a low subshrub of various vegetation types known as phrygana whereasHypericum empetrifolium
Willd. subsp.oliganthum (Rech. f.)Hagemann grows as a cushion-like dwarf shrub in chasmophyte associations rich in relic species.Hypericum empetrifolium
Willd. subsp.tortuosum (Rech. f.)Hagemann is confined in the high mountain regions and grows as a true dwarf espalier shrub with low spreading shoots.Dedicated to Hofrat Univ.-Prof. DrK. H. Rechinger on the occasion of his 80th birthday. 相似文献
10.
Synopsis The bloater, Coregonus hoyi, deposits its eggs on deep sediments (70–100 m in Lake Michigan), where its eggs and embryos can be exposed to epibenthic
predators. We investigated the vulnerability of early life intervals of bloaters to predation by mysids, Mysis relicta, which are mostly epibenthic by day and planktonic at night. Bloaters were raised from spawn in the laboratory and presented
to field-collected mysids in laboratory predation trials. Eggs were not ingested by the mysids. Embryonic bloaters were vulnerable
to predation by mysids only during the interval between hatching and swim up, usually 1–24 h under laboratory conditions.
The mysids required about a day of exposure to this novel prey before they were able to kill significant numbers of the bloater
embryos by making successive attacks with their thoracic legs. In experiments with experienced (2 and 3 days with bloater
embryos) mysids, a functional response between embryo density and mysid predation rates was apparent. Temperature and the
presence of alternative prey (zooplankton) did not alter the ‘kill rate’ (about 2.5 embryos mysid-1d-1) of experienced mysids at high bloater densities (>4 bloaters/mysid). However, more embryos were partially, rather than completely,
ingested at 4 versus 9° C and in the presence of zooplankton. 相似文献