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  • 1
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 35 (2008): L03402, doi:10.1029/2007GL032837.
    Description: Arctic rivers transport huge quantities of dissolved organic carbon (DOC) to the Arctic Ocean. The prevailing paradigm is that DOC in arctic rivers is refractory and therefore of little significance for the biogeochemistry of the Arctic Ocean. We show that there is substantial seasonal variability in the lability of DOC transported by Alaskan rivers to the Arctic Ocean: little DOC is lost during incubations of samples collected during summer, but substantial losses (20–40%) occur during incubations of samples collected during the spring freshet when the majority of the annual DOC flux occurs. We speculate that restricting sampling to summer may have biased past studies. If so, then fluvial inputs of DOC to the Arctic Ocean may have a much larger influence on coastal ocean biogeochemistry than previously realized, and reconsideration of the role of terrigenous DOC on carbon, microbial, and food-web dynamics on the arctic shelf will be warranted.
    Description: This material is based on work supported by the National Science Foundation under grant numbers OPP-0436106, OPP- 0519840, and EAR-0403962, and is a contribution to the Study of Environmental Arctic Change (SEARCH).
    Keywords: DOC ; Arctic ; Rivers
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: text/plain
    Format: application/pdf
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  • 2
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 30 (1989), S. 2607-2610 
    ISSN: 1089-7658
    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: A new class of Einstein's field equations with the energy-momentum tensor of a perfect fluid with nonlinear electromagnetic field aligned along the Debever–Penrose directions is determined. The solution obtained is a nonlinear electromagnetic generalization of the fluid NUT-B˜(+) [Newman–Unti–Tamburino and Carter B(+)] solution.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Male carp bred in outside ponds in Poland were sampled monthly from 5 to 46 months old, to analyse changes in gonadosomatic index (GSI) and pituitary gonadotropin hormone (GTH) in blood serum and in pituitary, 17α20β8P and 11KT in blood and gonadotropin releasing hormone (GnRH) in pituitary and hypothalamus. First signs of puberty with significant testis development (a high GSI of 12% and strong mitotic activity of the type-B spermatogonia) were seen at 13 months and 4548° days. By 16 months the GSI had declined to 6%. At 25 months the GSI remained at 6%, active spermatogenesis was observed, with some accumulation of spermatozoa but no spermiation. During the years 4 and 5 the GSI increased regularly from 6 to 12% and spermiation was observed nearly all the time. Some GTH was found in the blood before gonad development occurred. Thereafter there was no major change in GTH (10–20 ng ml−1 serum) except a peak of 200–130 ng ml−1 at 38. 39 months: this peak was not related to any major biological event, except that all fish reached spermiation at that time. A progressive increase of the amount of GTH in the pituitary was observed during the sampling period. Opposite fluctuations in the GnRH content were observed in brain and pituitary. Circulating 11-ketotesterone (11-KT) increased to 20 30 ng ml−1 serum in spring 22–25 months and at 36–37 months in parallel with the progressive rise of the water temperature, but independently of stage of testes development. These peaks of 11-KT were followed immediately (1984) or two months later (1983) by temporary major rises of 17αa-hydroxy-20β-dihydroprogesterone reaching 2–3 ng ml1 serum; this was not related to the temperature nor to the spermatogenetic stage.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Sexual maturation in sea trout (Salmo trutto L.) running up the River Calonne (Normandy, France), at the finnock stage, is characterized. Autopsy of 118 finnock in summer showed that 87 ± 7% aged 2+ and 33 ± 15% aged 1 + were undergoing gametogenesis. In autumn all the fish were maturing. The analysis of plasma levels of 11-ketotestosterone, 17β-oestradiol, maturational gonadotropin and vitellogenin showed that only females in vitellogenesis can be well identified in summer (plasma vitellogenin greater than 0.30 mg ml-1). The morphological recognition of females among 134 autumn finnock and the ELISA assay of plasma vitellogenin of 814 summer finnock, demonstrated that vitellogenic females represented 12 ± 2%0 of the 1 + individuals and 46 ± 2% of 2+ fish captured during the 1985 run. The question of a possible relationship between the salinity tolerance ofjuvenile trout migrating towards the sea in the spring and their age on first migration in the river is discussed.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 56 (2000), S. 0 
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The inherent ability of the carp Cyprinus carpio gut to absorb intact salmon gonadotropin hormone-releasing hormone analogue (sGnRH-a)+Pimozide (Pim), without loss of their bioactivity is very limited. Artificial intestinal absorption enhancement boosted sGnRH-a and Pim induced GtH II release and milt production significantly. The intraperitoneal route of administration was more effective than the oral one. A potential application of the oral route for peptidergic drug delivery and the possibility of developing a dietary delivery system is discussed.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 611 (1990), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of applied ichthyology 14 (1998), S. 0 
    ISSN: 1439-0426
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: A gonadoliberin analogue (GnRHa) whose biological role is the stimulation of gonadotropin (GTH II) secretion, has been encapsulated together with intestinal absorption enhancers and proteolytic enzyme inhibitors. The capsules have been coated to prevent their solubilization at acid pH in the stomach. After oral delivery of the capsules by forced-feeding, high GnRHa intestinal absorption and high bioavailability in the blood results. GTH II secretion was stimulated in a dose-dependent manner by the orally delivered GnRHa in three species having different digestive tract structures and different feeding habits: the rainbow trout, the common carp and the African catfish. In addition, the oral delivery of GnRHa also results in the induction of ovulation in all three species at doses similar to those usually used to induce spawning in these species. There was no competition of nutrient given together with the microcapsules on GnRHa absorption. From these results, it becomes possible to develop special diets containing microencapsulated bioactive peptides for use in therapy or to modify nonvital functions in fish. In the present case, an orally-induced ovulation treatment will be developed.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1439-0426
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Non-ionic surfactant–polyoxyethylene sorbitan monooleate (Tween-80) and oleic acid are food and pharmaceutical ingredients for oral and parenteral delivery and generally regarded as safe (GRAS). They have the potential as an intestinal absorption enhancer for the development of oral drug delivery systems. However, their safety in terms of mucosal integrity has yet to be evaluated. Therefore, the purpose of the present work was to study the tissue damaging effects of Tween-80, oleic acid and of their mixed micellar formulation (oleic acid + Tween-80). This was investigated at 2 h and 24 h after rectal delivery and compared with the topical effect of polyoxyethylene 9 lauryl ether (Polydocanol). The same experiment was carried out on three species with distinct feeding habits: the common carp, Cyprinus carpio (L.); the African catfish, Clarias gariepinus (Burchell); and the rainbow trout, Oncorhynchus mykiss (Walb.). Based on the findings of this study it was concluded that Tween-80 (4%), or its mixed micelle with oleic acid (0.6%) can be considered as a safe formulation, inducing only a moderate alteration of the intestinal mucosa, comparable to the effect of an isotonic saline. By contrast, in the three species, the same dose of Polydocanol, or of its mixed micelle with oleic acid, induced severe tissue damage of the intestinal mucosa, still present after 24 h. Mixed micelles of oleic acid with Tween-80 were also demonstrated as increasing the intestinal absorption of the salmon gonadotropin releasing hormone analogue (sGnRH-a) in catfish, C. gariepinus, and consequently stimulating GtH II secretion. This effect was compared with the action of other drugs considered as intestinal absorption enhancers.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    General and Comparative Endocrinology 91 (1993), S. 272-280 
    ISSN: 0016-6480
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    General and Comparative Endocrinology 67 (1987), S. 202-213 
    ISSN: 0016-6480
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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