Genetics: Beadle and Ephrussi
نویسنده
چکیده
2-a shaft of one diameter long-the angle of twist at a given radius plotted against v = z/a is practically a straight line from v = 0.5 to v = 1.5. That is, the influence of the terminal moments extends only about half a radius from the ends. The total angle of twist comes out to be about 5% more than the value predicted by the simple formula. For a very long shaft the effect of the non-linear distribution of the stresses at the ends disappears at a distance of about one radius. Note that B, = -1 for large k; then for large v, (15) reduces to its first term. This discussion has been limited to terminal loads having circular symmetry about the shaft axis z. It has shown that a non-linear symmetrical stress distribution at the ends does not change the linear relation derived by Saint-Venant and assumed by engineers. It is reasonable to infer that any type of distribution, symmetrical or not, will also be without appreciable influence.
منابع مشابه
Boris Ephrussi (1901-1979)
Boris Ephrussi studied fruit flies, yeast, and mouse [3] genetics and development while working in France and the US during the twentieth century. In yeast, Ephrussi studied how mutations in the cytoplasm persisted across generations. In mice he studied the genetics of hybrids and the development of cancer. Working with George Wells Beadle [4] on the causes of different eye colors in fruit flie...
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T HAS been shown that diffusible substances are involved in the differI entiation of certain eye colors in Drosophila melanogaster (EPHRUSSI and BEADLE 1937a; BEADLE and EPHRUSSI 1937). Fat bodies are concerned with the production of one of these substances (v+ substance); two substances (v+ and cn+ substances) can be obtained from the Malpighian tubes of flies of certain genotypes. Preliminary...
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Boris Ephrussi and George Wells Beadle [5] developed a transplantation technique on flies, Drosophila melanogaster [6], which they described in their 1936 article "A Technique of Transplantation for Drosophila [4]." The technique of injecting a tissue from one fly larva into another fly larva, using a micropipette, to grow that tissue in the second larvae, was a means for investigating developm...
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chromosomes apparently result from chromosome unbalance. Two types of control experiments indicate that the female-sterile host is not responsible for this behavior: Wild type diploid ovaries grown in fes hosts give rise to fully viable eggs, and from many normal diploid females into which superfemale ovaries had been implanted the offspring obtained were entirely from the normal ovaries of the...
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ROMINENT among the problems confronting present day genetP icists are those concerning the nature of the action of specific geneswhen, where and by what mechanisms are they active in developmental processes? Despite the recognized importance of such questions as these, relatively little has been done toward answering them, a situation not a t all surprising considering the difficulty of getting...
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HE development of vermilion eye color in mosaics of D. simulans is T not always autonomous (STURTEVANT 1932). By transplantation experiments BEADLE and EPHRUSSI (1936) have shown that the vermilion and cinnabar eye colors of D. melanogaster are not autonomous in development. Vermilion and cinnabar late larval eye discs develop the wild type pigment when transplanted to late wild type larvae. Ve...
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