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  • 2000-2004  (3)
  • 1980-1984  (3)
  • 1
    ISSN: 1745-6584
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences
    Notes: A conceptual model for ground water flow is presented for a fractured Silurian dolomite in the Niagara Escarpment area of southern Ontario. Such a model is necessary to facilitate remedial efforts of a PCB-contaminated site located in Smithville, Ontario. Both physical and chemical hydrogeological observations obtained from field investigations were used to deduce the structure of the ground water flow system in the fracture network. The field study was conducted using observations obtained from six bore-holes drilled in the vicinity of the town of Smithville. The boreholes were diamond cored through the entire thickness of the dolomite formation (approximately 45 m), hydraulically tested using a 2 m packer spacing and then completed using multipacker casing strings. Measurements of hydraulic head were obtained on a weekly basis over a period of two years, and ground water from each borehole interval was collected for geochemical analyses for inorganic and isotopic composition. Transmissivity measurements indicate that the dolomite is divided into two ground water flow systems separated by an extensive unit of low transmissivity that is pervasive throughout the region. The upper flow system is characterized by water enriched in Mg2+ and SO42-. Below the low transmissivity zone, ground water increases in salinity and is enriched in Ca2+ and SO42-. Based on the geochemistry, the rate of ground water migration in the lower flow system is surmised to be much less than that in the upper system. Measurements of hydraulic head in conjunction with the results of the analyses of the environmental isotopes (δ18O and δ2H) suggest that ground water flow is mainly horizontal and likely governed by enlarged bedding plane fractures. The isotope geochemistry and topographical features further suggest that ground water recharge is occurring approximately 2 km to the north of Smithville.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 23 (1983), S. 0 
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: A novel method for studying trophic dynamics of fish is described which involves X-raying animals which have been fed a diet labelled with metallic iron powder. Results of feeding studies on juvenile Atlantic salmon, Salmo salar L., are presented which demonstrate that food consumption and gastric evacuation rates can be measured without incurring the major disadvantages offeree feeding, starvation or autopsy which are associated with most of the established methods.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 25 (1984), S. 0 
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: After a pre-prandial period of starvation or feeding with unlabelled food, 0+ salmon parr (0.8–11.7 g) were fed a test meal of iron particle labelled food and subsequently were again either starved or fed unlabelled food. The quantity of labelled food consumed and the evacuation rate was determined by serial radiographs. In fish of all sizes, pre-prandial starvation causes a larger test meal (as a percentage of body weight) to be consumed when compared to pre-prandially fed fish. In addition, pre-prandial starvation results in relatively larger meals as a percentage of body weight being taken by smaller compared to larger fish. This result was not evident for pre-prandially fed fish. Evacuation rate was unrelated to body size irrespective of feeding history. Post-prandial starvation decreased evacuation rate but this effect was inversely related to the quantity of food consumed. Larger meals were not evacuated differently from smaller meals if feeding occurred post-prandially, irrespective of pre-prandial starvation.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 21 (1982), S. 0 
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Measurements of gut contents and changes in the volume and colour of bile in the gall bladder of juvenile Atlantic salmon are described for a variety of feeding regimes. The gall bladders of actively feeding fish are virtually empty of bile. When deprived of food, the weight of the gall bladder increases within 6 h and reaches a value equivalent to approximately 20% of the liver weight within 36 h. Bile is pale straw, green and blue in colour after 1, 4 and 6 days of starvation respectively. Stored bile is released from the gall bladder in response to food entering the anterior hind gut.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1365-2761
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 170 (2000), S. 505-509 
    ISSN: 1432-136X
    Keywords: Key words Ammonotelism ; Ureotelism ; Osmotic flux ; Arginine vasotocin ; Mesotocin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Oxygen consumption was measured in five Dermophis mexicanus and averaged (±SEM) 0.047 ± 0.004 ml O2 g−1 h−1. Carbon dioxide production averaged 0.053 ± 0.005 ml CO2 g−1 h−1 in the same five animals 1 week later. This metabolic rate is similar to metabolic rates of other Gymnophionans but lower than metabolic rates reported for Anurans and Urodeles. Total nitrogen excretion averaged 1.37 μmol N g−1 h−1 which is higher than that found for other amphibians. Of this, 82.5% (1.13 μmol N g−1 h−1) was in the form of urea while 17.5% (0.24 μmol N g−1 h−1) was in the form of NH3 + NH+ 4. Such ureotelism is typical of terrestrial amphibians like D. mexicanus. Osmotic water flux averaged 0.0193 ml g−1 h−1 in control (sham injected) animals and was not significantly altered by injection of either arginine vasotocin or mesotocin. This osmotic flux is similar to osmotic fluxes found for other terrestrial amphibians. The combined data suggest that metabolism in D. mexicanus is, like most other Gymnophionans, lower than other amphibians. The high rates of nitrogen (especially urea) excretion suggests that this fossorial animal accumulates urea like other burrowing amphibians.
    Type of Medium: Electronic Resource
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