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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Environmental science & technology 17 (1983), S. 272-277 
    ISSN: 1520-5851
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    International journal of cosmetic science 5 (1983), S. 0 
    ISSN: 1468-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: This paper reviews current ideas concerning the reactions involved in sunburn, suntanning, premature ageing and carcinogenesis due to acute or chronic exposure to sunlight. The physiological mechanisms of protection involving melanin pigmentation, thickening of the epidermal horny layer and urocanic acid are briefly discussed. The importance of wavelengths from 290-315 nm (UV-B) for these reactions is emphasized as is the need to investigate further the involvement of longer wavelength (UV-A, 315-400 nm). L'influence des radiations sur la peau et les principes de la protection solaire Cet article passe en revue les données actuelles concernant les réactions impliquées dans les processus de brûlure, bronzage, vieillissement prématuré et carcinogenese dus aux expositions aigues ou chroniques de la peau à la lumière solaire. Les mécanismes physiologiques de protection qui mettent en oeuvre la pigmentation par la mélanine, l'épais-sissement de la couche cornée, et l'acide urocanique sont brièvement discutés. On insiste sur l'importance des UV-B (longueurs d'onde de 290 à 315 nm) dans ces réactions, de même que sur la nécessité d'entreprendre des études plus approfondies sur le rôle des UV-A (315-400 nm).
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-2137
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Triticum aestivum L.) are maximized when the N supply contains a mixture of NH4 and NO3. Tillers per plant is the yield component most commonly increased by mixed N nutrition in greenhouse studies. The objective of this study was to evaluate, under field conditions, the response of 'Butte 86' spring wheat to N sources differing greatly in nitrification rate. Nitrogen was applied at 0 or 112 kg N ha-1; the N sources were calcium nitrate (CN), urea, urea-dicyandiamide (DCD), 0.1-g urea granules, and 0.1-g urea-DCD granules. Six field trials were performed. Topsoil (0-15 cm) analysis of fertilized plots during tillering indicated a wide range of mineral N contents (19-101 mg N kg-1) and of NH4;NO3 mole ratios (0.04-2.06). Correlation analyses suggested that tillering was sensitive to the total mineral N supply, but quite insensitive to the NH4;colon;NO3 ratio in the topsoil. Vegetative growth and N uptake were generally lower for CN than for the other N sources. At some locations, more heads per square meter at harvest were observed with the slower-nitrifying N sources. Grain yields were increased by N fertilization, but significant differences between N sources were not generally observed. For both years of the study, the 0.1-g urea-DCD granules gave the highest N uptake efficiency. However, the dramatic responses in growth, tillering, or grain yield routinely observed with mixed N nutrition in hydroponic or greenhouse studies could not be duplicated in the field.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract Pregnant goats were fed grass-legume silage grown on soil amended with 112 dry metric tons per hectare of municipal sewage sludge from Syracuse, New York for 135 days. Whereas PCBs were not detectable in control or sludge-grown silage, cadmium was much higher (3.81 ppm) in the sludge-grown silage as compared to the control silage (0.14 ppm). There were no consistent differences in residues of cadmium in the goat's milk or body tissues of the kids when compared to controls. The concentration of cadmium in the livers of the adult animals was significantly higher (p 〈 0.05) in the sludge treatment than controls. No significant treatment effects were observed in mutagenic responses for the goats milk. Interestingly, the pregnant goats fed the sludge-grown silage produced far too little milk for their kids while the control animals produced sufficient milk. There were no observable changes in the tissue ultrastructure as examined by electron microscopy for both the adults and the kids from either ration treatment.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Agronomy journal 91 (1999), S. 1046-1049 
    ISSN: 0002-1962
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 3 for spring wheat (Triticum aestivum L.) is common in the northern Great Plains. Two field sites were established in eastern North Dakota, with the objective of measuring the relative rate of fall and overwinter nitrification as influenced by two nitrification inhibitors, nitrapyrin and ammonium thiosulfate (ATS). Aqua ammonia was injected into the soil in early October 1996, alone, with nitrapyrin (0.56 and 1.68 kg ha−1), or with ATS (17 kg S ha−1). The N rate was 84 kg ha−1. The winter of 1996–1997 was very unusual, with about 3 m of snowfall—three times the average snowfall in southeastern North Dakota. Nitrapyrin and ATS were effective in slowing nitrification in the fall and both inhibitors increased the amount of mineral N found in the fertilizer bands in the spring at both sites. One site was planted to `Pioneer 2375' spring wheat. Overwinter N loss, presumably by denitrification, was severe. Amending the ammonia with nitrapyrin or ATS greatly increased wheat growth, N uptake, and grain yield. The apparent N uptake efficiency into the grain + straw was 24% for the unamended aqua ammonia, but was 50 to 56% when nitrapyrin or ATS was used. These results probably define a worst-case scenario regarding the performance of fall-applied ammonia in this area, and suggest that both nitrapyrin and ATS have value as nitrification inhibitors with fall-banded N.
    Type of Medium: Electronic Resource
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