79 research outputs found
Resonances of low orders in the planetary system of HD37124
The full set of published radial velocity data (52 measurements from Keck +
58 ones from ELODIE + 17 ones from CORALIE) for the star HD37124 is analysed.
Two families of dynamically stable high-eccentricity orbital solutions for the
planetary system are found. In the first one, the outer planets c and d are
trapped in the 2/1 mean-motion resonance. The second family of solutions
corresponds to the 5/2 mean-motion resonance between these planets. In both
families, the planets are locked in (or close to) an apsidal corotation
resonance. In the case of the 2/1 MMR, it is an asymmetric apsidal corotation
(with the difference between the longitudes of periastra ), whereas in the case of the 5/2 MMR it is a symmetric antialigned
one ().
It remains also possible that the two outer planets are not trapped in an
orbital resonance. Then their orbital eccentricities should be relatively small
(less than, say, 0.15) and the ratio of their orbital periods is unlikely to
exceed .Comment: 28 pages, 10 figures, 3 tables; Accepted to Celestial Mechanics and
Dynamical Astronom
Sex : the apes and us - 1983 Counterpoint Forum
Lectures given by Professor Roger Short, Professor of Physiology at Monash University and Bettina Arndt, broadcaster and writer for the 1983 Counterpoint Forum held in Lecture Theatre 1 at Murdoch University.
This sound recording is part of the History of Murdoch University Collection
Evaluating legume species as alternative trap crops to chickpea for management of Helicoverpa spp. (Lepidoptera: Noctuidae) in central Queensland cotton cropping systems
Mounting levels of insecticide resistance within Australian Helicoverpa spp. populations have resulted in the adoption of non-chemical IPM control practices such as trap cropping with chickpea, Cicer arietinum (L.). However, a new leaf blight disease affecting chickpea in Australia has the potential to limit its use as a trap crop.
Therefore this paper evaluates the potential of a variety of winter-active legume crops for use as an alternative spring trap crop to chickpea as part of an effort to improve the area-wide management strategy for Helicoverpa spp. in central Queensland’s cotton production region. The densities of Helicoverpa eggs and larvae were compared over three seasons on replicated plantings of chickpea, Cicer arietinum (L.), field pea Pisum sativum (L), vetch, Vicia sativa (L.) and faba bean, Vicia faba (L.). Of these treatments, field pea was found to harbour the highest densities of eggs. A partial life table study of the fate of eggs oviposited on field pea and chickpea suggested that large proportions of the eggs laid on field pea suffered mortality due to dislodgment from the plants after oviposition. Plantings of field pea as a replacement trap crop for chickpea under commercial conditions confirmed the high level of attractiveness of this crop to ovipositing moths. The use of field pea as a trap crop as part of an areawide management programme for Helicoverpa spp. is discussed
New ways of preventing HIV infection: thinking simply, simply thinking
HIV infection is the greatest health crisis in human history. It continues to spread unchecked among the poor in the developing world because we have failed to design simple preventative methods that are available and affordable to those living on under $2 a day. Five new methods are discussed. (i) A natural microbicide. Intravaginal lime or lemon juice has been used for centuries as a traditional contraceptive. The juice can also kill HIV in the laboratory, but clinical trials are needed to see if vaginal application is acceptable, safe and effective. (ii) Intravaginal oestrogen. Monkeys can be protected from Simian immunodeficiency virus (SIV) infection by keratinizing the vagina with topical oestrogen. If women take the oral contraceptive pill vaginally it retains its contraceptive efficacy, and the oestrogen it contains should thicken the vagina and protect against HIV infection. Clinical trials are needed. (iii) Male circumcision. Removal of the inner foreskin removes the main site of HIV entry into the penis, resulting in a sevenfold reduction in susceptibility to infection. The practice needs to be promoted. (iv) Post-coital penile hygiene. Wiping the penis immediately after intercourse with lime or lemon juice or vinegar should kill the virus before it has had a chance to infect. A clinical trial of efficacy is needed. (v) PhotoVoice. Asking schoolchildren in developing countries to photograph their impressions of HIV/AIDS is a powerful way of getting them to discuss the subject openly, and develop their own preventative strategies
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