Influence of the Predation of Orius sp. (Hemiptera: Anthocoridae) on the Aphid Population in a Soy-bean Field; an Example of Interrelation Between a Polyphagous Predator and its Principal Prey

In general, minute pirate bugs are known as natural enemies of small insects and mites; while some species feed on specific prey (Anderson, 1962a, b), others are known to be polyphagous (Barber, 1936, and others). It goes without saying that in order to evaluate a predatory insect’s role as a natural enemy, it is necessary to clearly identify the prey (Thompson, 1951); however, in the case of polyphagous predators it is essential to consider not only the preference as food of each prey species as emphasized by Anderson (1962b), but also the behavior and population density of each prey species. We have discovered that the predation of aphids by species of the genus Orius, which are found in large numbers in soybean fields in the Tohoku (Northeast) region, is influenced by the behavior and population density of 2 or 3 other prey species that appear concurrently with the aphids. The results of the study are reported here.Originating text in Japanese.Citation: Oku, Toshio, Kobayashi, Takashi. (1966). Influence of the Predation of Orius sp. (Hemiptera: Anthocoridae) on the Aphid Population in a Soy-bean Field; an Example of Interrelation Between a Polyphagous Predator and its Principal Prey. Japanese Journal of Applied Entomology and Zoology, 10, 89-94

Repeated Stressing and Crystalline State of Annealed Steel

The action of repeated loading, especially of repeated compression for the crystalline state of 0.41% carbon steel was investigated by X-ray. As a result it was established that the crystal fragmentation occurs when the maximum stress exceeds the lower yield point of that material but has no direct relation with fatigue failure. In the case of alternate tension and compression with equal amplitude (mean stress equals zero), the specimens break down far below the yield point, of course, but is not necessarily preceeded by the crystal fragmentation. Then, what is the true nature of fatigue of metals is our problem. According to the authors' view, failure begins when the accumulation of crystal distorsion exceeds a certain limit proper to the individual grain

Quantitation and Visualization of Ultraviolet Induced DNA Damage Using Specific Antibodies

The major types of DNA damage induced by sunlight in the skin are DNA photoproducts, such as cyclobutane pyrimidine dimers (CPDs), (6-4)photoproducts (6-4PPs) and Dewar isomers of 6-4PPs. A sensitive method for quantitating and visualizing each type of DNA photoproduct induced by biologically relevant doses of UV or sunlight is essential to characterize DNA photoproducts and their biologlcal effects. We have established monoclonal antibodies specific for CPDs, 6-4PPs or Dewar isomers. Those antibodies allow one to quantitate photoproducts in DNA purified from cultured cells or from the skin epidermis uslng an enzyme-linked immunosorbent assay. One can also use those specific antibodies with in situ laser cytometry to visualize and measure DNA photoproducts in cultured cells or in the skin, using indirect immunofluorescence and a laser-scannlng confocal microscope. This latter method allows us to reconstruct three-dimensional images of nuclei containlng DNA photoproducts, and to simultaneously examine DNA photoproducts and histology in multilayered epidermis. Using those techniques, one can determine the induction and repair of these three distinct types of DNA photoproducts in cultured cells and in the skin exposed to sublethal or suberythematous doses of UV or solar simulated radiation. As examples of the utility of these techniques and antibodies, we describe the DNA repalr kinetics followlng irradiation of human cell nuclei and the photoprotective effect of melanin against DNA photoproducts in cultured pigrlented cells and in human epidermis

Destabilizing Heegaard splittings of knot exteriors

AbstractWe give a necessary and sufficient condition for Heegaard splittings of knot exteriors to admit destabilizations. As an application, we show the following: let K1 and K2 be a pair of knots which is introduced by Morimoto as an example giving degeneration of tunnel number under connected sum. The Heegaard splitting of the exterior of K1#K2 derived from certain minimal unknotting tunnel systems of K1 and K2 is stabilized

Finite multiplicity theorems for induction and restriction

We find upper and lower bounds of the multiplicities of irreducible admissible representations $\pi$ of a semisimple Lie group $G$ occurring in the induced representations $Ind_H^G\tau$ from irreducible representations $\tau$ of a closed subgroup $H$. As corollaries, we establish geometric criteria for finiteness of the dimension of $Hom_G(\pi,Ind_H^G \tau)$ (induction) and of $Hom_H(\pi|_H,\tau)$ (restriction) by means of the real flag variety $G/P$, and discover that uniform boundedness property of these multiplicities is independent of real forms and characterized by means of the complex flag variety.Comment: to appear in Advances in Mathematic