Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Ground Water Flow in a Fractured Carbonate Aquifer Inferred from Combined Hydrogeological and Geochemical Measurements (2000)
    Oxford, UK : Blackwell Publishing Ltd
    Ground water 38 (2000), S. 0 
    Details
    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
    URL: http://dx.doi.org/10.1111/j.1745-6584.2000.tb00220.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The use of body water, sodium, potassium and calcium content to investigate the nutritional status of first year Atlantic salmon parr in two Scottish Highland streams (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 44 (1994), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Water content of Atlantic salmon parr fell from about 84% at emergence (late May) to just under 79% in September but rose again towards March. Na+ content consequently rose from 3·3 mg g−1 dry wt at the beginning of June to 6·2 mg g−1 in early July. It then fell to 4·4 mg g−1 in September, rising again towards March. K+ content rose to a maximum in July to stabilize at 16·6 mg g−1 dry wt in September. The resultant Na+/K+ ratio peaked at 0·43: 1 in mid-June, falling to a minimum in mid-August but rising again in March reflecting changes in the relative proportions of intra and extracellular water. The changes in whole-body chemistry suggest a period of nutritional stress immediately after emergence and during the winter. In streams at higher altitude and of lower nutrient status, nutritional stress during the winter appears to be more severe.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1994.tb01245.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    The use of whole-body sodium, potassium and calcium content to identify the nutrient status of first year salmon fry (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 43 (1993), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Samples of fed and unfed hatchery reared Atlantic salmon fry and parr were analysed for body water and whole body Na, K and Ca content. From these body parameters it is possible to estimate the relative proportions of the skeletal mass, and intra- and extracellular spaces. These data can be applied to estimating the nutritional status of parr sampled at random from hatchery, and possibly from wild populations. When fish with a dry weight of about 25 and 70 mg were deprived of artificial food for 27 and 21 days, respectively, the Na/K ratio rose to 0.59 and 0.80 compared with 0.37 in the controls. With fish of about 475 mg in weight, percentage water content was a better indicator of undernourishment. The use of the K+: Ca2+ ratio to compare the amount of cellular material with the skeletal mass was a good indicator of nutritional depletion, especially in smaller fish.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1993.tb01158.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Thermal Convection in the Archaean Crust? (1968)
    [s.l.] : Nature Publishing Group
    Nature 220 (1968), S. 552-556 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Two genetic models have been compared for a tectonic pattern typical of undisturbed remnants of Archaean crust. A model implying simple thermal convection in a granodioritic crustal layer is found to have advantages over the classic model assuming the gregarious batholiths of Rhodesia to be granite ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/220552a0
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Pattern of feed intake in four species of fish under commercial farming conditions: implications for feeding management (1999)
    Oxford, UK : Blackwell Science Ltd
    Aquaculture research 30 (1999), S. 0 
    Details
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Meal duration and feed ingestion rate were measured in sea cage-reared Atlantic salmon Salmo salar, rainbow trout Oncorhynchus mykiss, yellowtail Seriola quinqueradiata and red sea bream Pagrus major fed dry extruded feed in discrete meals. At the population level, satiation times in yellowtail, salmon and trout were typically about 15–25 min, but time to satiation was longer (60–90 min) in red sea bream. In all species, feed ingestion rate declined progressively during the course of the meal as the fish became satiated. Initial feed ingestion rates in salmon were ≈ 0.3–0.5 kg feed tonne fish–1 min–1 and in trout 0.5–0.9 kg feed tonne fish–1 min–1, although the capacity to deliver feed may have restricted ingestion. Water temperature had little effect on ingestion rates, possibly because the number of meals per day (1–3) was varied with water temperature, and this may have standardized hunger level at the start of meals. Yellowtail ingested feed at ≈ 3.5 kg feed tonne fish–1 min–1 at water temperatures of 18 °C and 28 °C, whereas red sea bream ingested feed at initial rates of 0.6 and 1.4 kg feed tonne fish–1 min–1at 26.5 °C and 18 °C respectively. The findings are discussed in relation to feeding strategies to minimize interfish competition for feed and to improve the ability of fish farmers to detect the point at which fish are satiated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2109.1999.00369.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Effects of temperature, salinity, desiccation and chemical treatments on egg embryonation and hatching success of Benedenia seriolae (Monogenea: Capsalidae), a parasite of farmed Seriola spp. (2005)
    Oxford, UK : Blackwell Science Ltd
    Journal of fish diseases 28 (2005), S. 0 
    Details
    ISSN: 1365-2761
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The effects of temperature and salinity on the embryonation period and hatching success of eggs of Benedenia seriolae were investigated. Temperature strongly influenced embryonation period; eggs first hatched 5 days after laying at 28 °C and 16 days after laying at 14 °C. The relationship between temperature and embryonation period is described by quadratic regression equations for time to first and last hatching. Hatching success was 〉70% for B. seriolae eggs incubated at temperatures from 14 to 28 °C. However, no B. seriolae eggs embryonated and hatched at 30 °C and 〈2% of eggs hatched when incubated at 24 °C after transfer to 30 °C for 48 h. Embryonation period was similar for eggs incubated in sea water at 25, 30 and 35‰ salinity, but increased for eggs incubated at higher or lower salinities. When incubated at salinities ranging from 25 to 45‰, more than 70% of B. seriolae eggs embryonated and hatched. Hatching success was lower at 20 and 50‰ salinity and few or no eggs hatched at 10 and 15‰. Hatching of B. seriolae eggs can be prevented by desiccation for 3 min, by immersion in water at 50 °C for 30 s or by treatment with 25% ethanol for 3 min.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2761.2004.00605.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Infections of Seriola quinqueradiata Temminck & Schlegel and S. dumerili (Risso) in Japan by Benedenia seriolae (Monogenea) confirmed by morphology and 28S ribosomal DNA analysis (2001)
    Oxford UK : Blackwell Science Ltd
    Journal of fish diseases 24 (2001), S. 0 
    Details
    ISSN: 1365-2761
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2761.2001.00309.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Epitaxial salt reefs and mushrooms in the southern Dead Sea (1996)
    Oxford, UK : Blackwell Publishing Ltd
    Sedimentology 43 (1996), S. 0 
    Details
    ISSN: 1365-3091
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: Salt usually accumulates in shallow ephemeral brines as simple flat beds. However, in permanent brines deepening in solar evaporation ponds in the southern Dead Sea, salt accumulation is complicated by the growth of isolated vegetable-like salt structures and networks of polygonal salt walls. These walls divide large salt ponds, which are easily homogenized by wind, into thousands of small compartments that are less easy to mix. Instead, brines in the compartments stratify when a surficial layer about 10 cm thick supersaturates and floats above the cumulate floors on brines that are merely saturated.Salt reef growth in the southern Dead Sea has previously been attributed to mixing of ions common to brines already in the ponds and those pumped in from the northern basin (with or without subsurface brines rising through the pond floors). A new factor is emphasized here that, whatever the origins of the brines, salt reefs remain emergent by epitaxis, the in situ growth of crystalline substrates already in the surficial supersaturated layer.Epitaxis can be invisible in crystal clear brines and prolongs the obvious crystallization season by replacing sedimentation of grains nucleated and grown on the brine surface as the dominant mechanism of deposition. Salt reefs develop botryoidal overhangs that can merge into salt platforms that roof over deep brines. Salt shallows on the reef platforms and around the pond shores are both characterized by the deposition of the thin flat beds with vertical palisade textures well known from other ephemeral brines. Salt reefs are interpreted as tepee structures which have grown by epitaxis as fast as saturated brines have deepened around them. Epitaxis may also account for the rapid deposition of thick beds of pure salt in rifts that open to oceans.Local histories of salt reef compartmentalization can be read from the shapes of reefs that record their relative rates of growth and drowning. Rather than diminish evaporation area, damp emergent salt reefs act as giant transpirative pumps that accelerate salt crystallization and reconfigure the evaporation ponds into areas smaller than thought necessary by chemical engineers. The natural end of reef formation may be when shallow brines on hollow reef platforms become ephemeral on solid salt flats. Former salt reefs are likely to be distinguishable in the undeformed geological record by their botryoidal layers of nonvertical chevron crystals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3091.1996.tb01517.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Simon Bredon (c. 1300-1372) Physician, Mathematician and Astronomer (1962)
    Cambridge : Cambridge University Press
    The @British journal for the history of science 1 (1962), S. 19-30 
    Details
    ISSN: 0007-0874
    Source: Cambridge Journals Digital Archives
    Topics: History , Natural Sciences in General
    Notes: SynopsisSimon Bredon was one of a remarkable group of scientists who brought fame to Oxford by their achievements in the sphere of natural science, particularly in astronomy. Though his interests lay chiefly in the field of medicine, as indicated by the large collection of books on this subject which he bequeathed to his friends, he was also a mathematician and astronomer.The manuscripts of his works, still preserved at Oxford, Cambridge and the British Museum, which include an arithmetic, a commentary on the Almagest, a theory of the planets and astronomical calculations, have never been properly examined and some kind of preliminary investigation seems necessary before his true position among the Merton school of scientists can be assessed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1017/S0007087400000066
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Auditing nutrient discharges from fish farms: theoretical and practical considerations (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Aquaculture research 26 (1995), S. 0 
    Details
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Nutrient discharges from fish farms can be determined retrospectively, simply and with a high degree of accuracy from records of fish production and feed conversion ratios (FCR), combined with chemical analyses of feed and fish. Prospective prediction of the inputs (via feed and outputs) via production and discharges) of given chemical elements, on a daily basis and over longer periods of time, would represent a valuable management tool for farmers, and for regulatory and planning authorities. A dynamic model is presented for Atlantic salmon, Salmo salar L., which integrates biomass, growth rate. FCR. and nutrient retention and discharges in relation to feeding rate, diet composition and environmental factors. In view of the importance of feeding rate on growth, FCR and nutrient discharges, three simulation alternatives were modelled; namely, feeding 50%. 75 or 100% of the estimated maximum daily ration of a specified diet to salmon smolts of 80 g initial weight over a period of one year in sea water. The 50 and 75% rations, in comparison with 100% ration, showed dramatic reductions in fish weight after one year (0.4 and 1.4 kg versus 3.3 kg). The discharges of nitrogen (N) and phosphorus (P) per unit biomass production were reduced to some extent in the first months of the simulation period, and thereafter, there were no clear differences in discharges of N and P per unit biomass at the three ration levels. However, the accumulated N and P discharges per unit weight gain were slightly increased on the 75% ration, and two-fold higher on the 50% ration compared to the 100% ration. The FCR was also higher in fish fed the lower rations. The simulation result indicates that reduced ration is not effective strategy for minimizing nutrient discharges from fish farms. In order to control discharges within any limits and to utilize the resources optimally, it is better to adjust the biomass on the farm and to feed the fish to appetite, at which growth rate is maximum and FCR is minimum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2109.1995.tb00960.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...