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  • Bactrocera dorsalis  (1)
  • Key words: Ovulation  (1)
  • 79.40
  • Polymer and Materials Science
  • Springer  (2)
  • 1995-1999  (2)
  • 1975-1979
  • 1997  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of mathematical biology 36 (1997), S. 95-118 
    ISSN: 1432-1416
    Keywords: Key words: Ovulation ; Lacker models ; Polycystic ovary syndrome ; PCOS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract.  The control of ovulation in mammalian species appears to be a highly robust process. The primary mechanism is believed to be competition amongst a group of developing follicles, mediated by a hormonal feedback loop involving in the first instance the pituitary. Successful follicles reach maturity and ovulate, the remainder atrophy and die. A model of this control process has been derived by Lacker and his group. Based on simple qualitative assumptions about the hormonal feedback loop, this is able to reflect many of the basic physiological features of ovulation in mammals. However, a fundamental hypothesis of Lacker’s work is that all follicles are identical and respond to hormonal signals in precisely the same way. Not only is this improbable, but it also leads to several aspects of the model which are qualitatively unrealistic, most notable of these is its inability to accurately model the condition known as Polycystic Ovary Syndrome. This common malfunction of the ovulatory control mechanism accounts for up to three-quarters of cases of anovulatory infertility in humans and its understanding is therefore of considerable medical significance. In this paper we extend the analysis of Lacker’s model to the case of non-identical follicles; this allows us to obtain behaviour much closer to that observed in PCOS patients and to draw some tentative conclusions about the mechanisms underlying this condition.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-1561
    Keywords: Oriental fruit fly ; Bactrocera dorsalis ; female attractant ; panax ; fruit fly control ; semiochemicals ; kairomones ; Tephritidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Fresh whole leaves and solvent–water leaf extracts of the hedgerow plant panax, Polyscias guilfoylei (Bull), were tested for their attractiveness to male and female Oriental fruit flies, Bactrocera dorsalis, in laboratory flight tunnel and cage olfactometer bioassays. Fresh mature whole panax leaves were found to be attractive to mated female oriental fruit flies in the flight tunnel. Response of males and virgin females was low and in most instances not significantly different from controls. Attraction of mated female flies to the layers resulting from a methylene chloride–water partition or a hexane–water partition of freshly ground leaves using small McPhail traps was greatest in the methylene chloride fraction. When methylene chloride and water layers were tested competitively in a multiple-choice rotating olfactometer, the methylene chloride fraction was more attractive. Tests involving the methylene chloride–water interface (an emulsion of the two partitioned layers) with and without a standard attractant NuLure, showed the emulsion layer to be significantly more attractive than the other fractions or NuLure. In outdoor cage olfactometer assays of methylene chloride and water fractions, activity was greatest in the methylene chloride fraction. The results suggests that volatile semiochemicals from this nonhost plant are attractive to mated female Oriental fruit flies. The results are discussed in relation to the chemical ecology of B. dorsalis and the potential use of this nonhost plant for detection and control of female Oriental fruit flies in the field.
    Type of Medium: Electronic Resource
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