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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Annales geophysicae 15 (1997), S. 1548-1556 
    ISSN: 0992-7689
    Keywords: Auroral ionosphere ; Magnetosphere-ionosphere interactions ; MHD waves and instabilities HF Dopplre ; ULF Waves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract A quantitative study of observations of the ionospheric signatures of magnetospheric ultra low frequency (ULF) waves by a high-latitude (geographic: 69.6°N 19.2°E) high-frequency Doppler sounder has been undertaken. The signatures, which are clearly correlated with pulsations in ground magnetometer data, exhibit periods in the range 100–400 s and have azimuthal wave numbers in the range 3–8. They are interpreted here as local field line resonances. Phase information provided by O- and X-mode Doppler data support the view that these are associated with field line resonances having large azimuthal scale sizes. The relative phases and amplitudes of the signatures in the Doppler and ground magnetometer data are compared with a model for the generation of Doppler signatures from incident ULF waves. The outcome suggests that the dominant mechanism involved in producing the Doppler signature is the vertical component of an E × B bulk motion of the local plasma caused by the electric field perturbation of the ULF wave.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0992-7689
    Keywords: Ionosphere (active experiments) ; Radio science (instruments and techniques) ; Space plasma physics (instruments and techniques)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract SPEAR is a new polar cap HF radar facility which is to be deployed on Svalbard. The principal capabilities of SPEAR will include the generation of artificial plasma irregularities, operation as an ‘all-sky’ HF radar, the excitation of ULF waves, and remote sounding of the magnetosphere. Operation of SPEAR in conjunction with the multitude of other instruments on Svalbard, including the EISCAT Svalbard radar, and the overlap of its extensive field-of-view with that of several of the HF radars in the SuperDARN network, will enable in-depth diagnosis of many geophysical and plasma phenomena associated with the cusp region and the substorm expansion phase. Moreover, its ability to produce artificial radar aurora will provide a means for the other instruments to undertake polar cap plasma physics experiments in a controlled manner. Another potential use of the facility is in ‚field-line tagging’ experiments, for coordinated ground-satellite experiments. Here the scientific objectives of SPEAR are detailed, along with the proposed technical specifications of the system.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Soil use and management 14 (1998), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Phosphorus budgets have been compiled for two contrasting grassland farming systems in the UK; intensive dairy farming and extensive hill sheep production. Balance sheets of inputs, recycling of P through the soil–plant–animal pathway and outputs are presented to determine the potential rate of P accumulation in the two systems. A typical 57 ha intensive dairy farm with 129 lactating cows imports 2.48t P via fertilizer, bedding and concentrates, plus a small amount from the atmosphere, of which 0.98t are exported in milk, calves and transfer from soil to the aquatic environment. Therefore 1.5t of P are retained within the farm each year, which equates to an accumulation rate of 26 kg/ha in the plant-soil system. This surplus occurs despite a fertilizer input of only 16 kg/ha. However, a large proportion of P, equivalent to 27 kg/ha, is imported in feed concentrates.For the typical 841 ha hill sheep farm supporting 694 Blackface ewes, P inputs and outputs are 0.66 and 0.42 t/yr, respectively. Therefore, approximately 0.24t P are retained within the farm, which is equivalent to an accumulation rate of 0.28 kg/ha per yr. In comparison to the small annual inputs and outputs of P on the hill farm, much P, 2.48t, is recycled through the plant-soil and plant-animal-soil pathways on the hill sheep farm. For both farming systems there is a net input of P, although the rate of accumulation is ten times greater for the dairy farm where the annual retention of P represents 60% of the total P inputs, compared with 36% on the hill sheep farm.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    European journal of soil science 48 (1997), S. 0 
    ISSN: 1365-2389
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Compositional differences between soil solutions obtained by different methods have frequently been reported; variations in the soi1: solution ratio may explain these results. In this study we compared the amount and composition of phosphorus (P) in soil leachates and soil solutions from a temperate grassland soil in northeast Scotland and determined the influence of soi1:solution ratio on P fractions in soil water extracts. Leachates were collected from intact soil cores over 6 months, the cores were then destructively sampled, and soil solutions obtained by centrifuging. Molybdate reactive P (MRP) represented 71% of the total dissolved P (TDP) in soil leachates but only 54% in soil solutions. The MRP component in soil water extracts increased from 71% to 92% as the soi1:solution ratio increased from 1:15 to 1:15·4, while the dissolved organic P (DOP) component decreased from 26% to 6%. As the soil:solution ratio increased the amount of MRP extracted increased; by contrast the amount of DOP and dissolved condensed P (DCP) extracted remained constant. While the MRP component is regulated by soil sorption processes, the supply and amount of DOP and DCP is probably related to biological activity. Dissolved organic carbon (DOC) extracted at wide soi1:solution ratios contained a smaller proportion of P than that extracted at narrower ratios. The results indicate differences in the behaviour of P fractions in the soil at various soi1:solution ratios and that these are reflected in the P composition of soil solution and leachate.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Plant pathology 32 (1983), S. 0 
    ISSN: 1365-3059
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Field trials for the control of Xiphinema diversicaudatum and Longidorus elongatus in a peat soil, L. macrosoma in a fine sandy loam soil, and L. attenuatus and L. leptocephalus in a sandy soil were done using 1,3-dichloropropene applied at various rates injected to either 15 cm or split injected at cither 15 and 30 cm or 15 and 45 cm. Good control of all the nematode species was obtained at two of the three sites to at least 60 cm though very intensive sampling revealed small residual populations following most treatments. The degree of control achieved at these two sites would probably reduce the risk to high-grade strawberry nursery stock grown on the sites from reservoirs of virus outside the site.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Industrial & engineering chemistry 40 (1948), S. 284-293 
    ISSN: 1520-5045
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Community dentistry and oral epidemiology 12 (1984), S. 0 
    ISSN: 1600-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract A sample of 314 consecutive women attending for their first antenatal visit at a public hospital were examined according to the WHO survey procedure. The women's age ranged from 16 to 42 yr with a mean of 23.5 yr. Only 3% were edentulous in both jaws, but 13% had some form of denture. A quarter had pocketing in at least one sextant and only 16% were free of gingivitis. The average number of DMF teeth was 15.8, comprising 2.7 decayed, 4.5 missing and 8.6 filled teeth; 70% had teeth needing restoration and 10% had at least one tooth needing extraction. There were significant relationships between DMF score and age (positive) and between number of teeth needing restoration and age, educational level, and the woman's own perception of her dental health (all inverse). Some form of dental attention was needed by 86% of the women; 12% had conditions needing immediate attention. By comparison with a 1971 study of pregnant women in Brisbane, there has been a marked decline in DMFT score (from 19.1 to 15.8).
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 202 (1964), S. 775-778 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] BEFORE a benzene ring is opened by means of the oxygenases possessed by bacteria which metabolize aromatic compounds, it appears that two hydroxyl groups must first be introduced into the nucleus. When catechol or protocatechuic acid (3 : 4-dihydroxybenzoic acid) results from these initial ...
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract Chemical analyses revealed that polycyclic aromatic hydrocarbons (PAHs) and other organic compounds were present in a perennial freshwater stream that flowed through the abandoned American Creosote Works and into Pensacola Bay, Florida. Moreover, groundwater pumped from a well depth of 21 m at a location adjacent to the site was heavily contaminated with PAHs and other organics. A study was conducted to determine the efficacy of ultrafiltration for removal of organics from groundwater at this U.S. Environmental Protection Agency, Super Fund site. Ultrafiltration reduced the concentration of total identified organics from 210.0 mg/L in groundwater to 1.5 mg/L in the post-filtration permeate. Tests for toxicity/teratogenicity in embryonic inland silversides,Menidia beryllina; and Microtox® 15 min EC50's were conducted with: 1) streamwater, 2) untreated ground-water, 3) feedwater used in the ultrafiltration system and 4) permeate water that passed through the ultrafiltration system. A concentration of 100% streamwater caused significant (α⩽0.05) teratogenic responses in fish embryos and larvae; the Microtox® EC50 was 3.7% streamwater. Groundwater and feedwater caused significant embryo toxic or teratogenic responses at concentrations of 100, 10, and 1%; the Microtox EC50's were 0.85 and 0.48%, respectively. In contrast, only 100% permeate water caused significant increases in terata, compared to the control response; at 10 and 1% concentrations 〉90% of hatched larvae appeared normal. The Microtox EC50 was 30% permeate water.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Archives of environmental contamination and toxicology 36 (1999), S. 13-20 
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract. Artificially weathered crude oil was degraded by four diverse cultures of mixed marine bacteria under optimized conditions for 7 and 14 days. Loss in total weight of starting oil (30 g) ranged from 6.8–17.3% in biologically active incubations compared with only 0.9–1.1% in sterile and nutrient-limited controls. In all incubations, both neutral and acidic water-soluble fractions (WSF) were accumulated. In biologically active systems, 50.9–249.0 mg neutral and 63.3–406.8 mg acidic WSF were accumulated whereas only 6.5–11.1 mg neutral and 1.7–2.2 mg acidic WSF were accumulated in control incubations. Analysis by gas chromatography demonstrated that accumulated WSF in biologically active systems contained compounds different from those washed from the starting crude oil. Exposure of grass shrimp (Palaemonetes pugio) embryos to neutral WSF from each of the biologically active cultures resulted in high embryo mortalities relative to sterile and nutrient-limited controls which exhibited 〉90% hatching success and larval survival. Toxicity of neutral WSF was also demonstrated on larvae of mysids (Mysidopsis bahia). In both cases, toxicity occurred only on exposure to neutral material accumulated by active, oil-degrading cultures and not with material washed from the weathered crude oil. These results imply that unique compounds were accumulated during degradation that may have been responsible for increased toxicity.
    Type of Medium: Electronic Resource
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