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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Order 10 (1993), S. 105-110 
    ISSN: 1572-9273
    Keywords: 06A07 ; 06A12 ; 05E25 ; 20B25 ; Automorphism ; isotone self-map ; irreducible element
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract For an ordered setP letP P denote the set of all isotone self-maps on P, that is, all mapsf fromP toP such thatx≥y impliesf(x)≥f(y), and let Aut (P) the set of all automorphisms onP, that is, all bijective isotone self-maps inP P . We establish an inequality relating ¦P P ¦ and ¦Aut(P)¦ in terms of the irreducibles ofP. As a straightforward corollary, we show that Rival and Rutkowski's automorphism conjecture is true for lattices. It is also true for ordered sets with top and bottom whose covering graphs are planar.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1572-9702
    Keywords: Methomyl ; bendiocarb ; toxicity ; action ; Acaridae.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Methomyl was 15 and 31.3 times more toxic than bendiocarb to bulb mites at the LC50 and LC90 values respectively. However, methomyl (pI50 3.0) was at least 126 times less active than bendiocarb (pI50 5.1) as an inhibitor of bulb mite cholinesterase in vitro. The disparity between the high toxicity of methomyl and its extremely low activity as an inhibitor of mite cholinesterase in vitro indicated that another mechanism was likely involved in its toxic action. Pharmacokinetic studies of methomyl and bendiocarb showed that penetration and metabolism were rapid and that there were no substantial differences in the internal levels of the respective parent carbamates during the 24 h test period. However, volatile radioactive material(s), some of which was carbon dioxide, was produced in appreciably greater amounts from methomyl than from bendiocarb. We speculate that the production of volatiles, such as carbon dioxide, acetonitrile and/or methylamine, may contribute to the toxicity of methomyl to bulb mites. © Rapid Science Ltd. 1998
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Machine learning 15 (1994), S. 321-329 
    ISSN: 0885-6125
    Keywords: Decision trees ; noise ; induction ; unbiased attribute selection ; information-based measures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract A fresh look is taken at the problem of bias in information-based attribute selection measures, used in the induction of decision trees. The approach uses statistical simulation techniques to demonstrate that the usual measures such as information gain, gain ratio, and a new measure recently proposed by Lopez de Mantaras (1991) are all biased in favour of attributes with large numbers of values. It is concluded that approaches which utilise the chi-square distribution are preferable because they compensate automatically for differences between attributes in the number of levels they take.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Machine learning 15 (1994), S. 321-329 
    ISSN: 0885-6125
    Keywords: Decision trees ; noise ; induction ; unbiased attribute selection ; information-based measures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract A fresh look is taken at the problem of bias in information-based attribute selection measures, used in the induction of decision trees. The approach uses statistical simulation techniques to demonstrate that the usual measures such as information gain, gain ratio, and a new measure recently proposed by Lopez de Mantaras (1991) are all biased in favour of attributes with large numbers of values. It is concluded that approaches which utilise the chi-square distribution are preferable because they compensate automatically for differences between attributes in the number of levels they take.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Experimental and applied acarology 20 (1996), S. 215-222 
    ISSN: 1572-9702
    Keywords: Clofentezine ; toxicity ; metabolism ; Acaridae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Clofentezine was toxic to bulb mite, Rhizoglyphus echinopus (Fumouze and Robin), eggs and larvae; however, it was not toxic to adults alone or in the presence of piperonyl butoxide. When adults were exposed to radioactive clofentezine, the acaricide was absorbed, metabolized and excreted. After 48 h exposure, 49.8% of the recovered radiocarbon was parent compound with 37.1, 9.1 and 3.6% detected in the container rinse, mite rinse and internal fraction, respectively. Homogenates of adults extensively metabolized clofentezine. The most active fraction was the 12 000 g supernatant plus glutathione followed in decreasing order by the supernatant, supernatant plus NADPH and the whole homogenate, each of which metabolized at least 16% of the acaricide. In the presence of piperonyl butoxide, in vitro metabolism of clofentezine by each of these active fractions was increased approximately 10%. Although it is possible that rapid metabolism could have contributed to the lack of toxicity of clofentezine to bulb mite adults, it is more likely that another major mechanism was involved. Perhaps adult bulb mites lack the sensitive target found in immature mites.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Experimental and applied acarology 22 (1998), S. 343-351 
    ISSN: 1572-9702
    Keywords: Acaricides ; toxicity ; Acaridae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Using a continuous exposure technique, the toxicity of 35 compounds to the bulb mite, Rhizoglyphus echinopus (Fumouze and Robin) was examined after 48 h. Sixteen acaricides yielded an LC50 of 〈1.0 mg cm2. The highest toxicity was exhibited by cyclodiene GABA antagonists (dieldrin, endrin and aldrin), some organophosphate (chlorpyrifos, diazinon and azinphosethyl) and carbamate (carbofuran) anticholinesterases and a thiazolidine flubenzimine. Oxythioquinox, fenazaflor, fenazaquin and amitraz were less toxic than the cyclodienes, organophosphates and carbamates. The sodium channel agonists (DDT and pyrethroids) and several specific acaricides with other modes of action were inactive (LC50 〉11.0 mg cm-2).
    Type of Medium: Electronic Resource
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