Meiotic Chromosome Behaviours in M1 Generation of Bread Wheat irradiated by Gamma-rays

SUMMARYEuploid and aneuploid plants of Triticum aestivum, variety Chinese Spring were pollinated with, pollen of Hordeum bulbosum. Euhaploids and aneuhaploids of Chinese Spring were obtained from the crosses. Meiotic chromosome pairing was analysed in 25 different aneuhaploids and the results were compared with those obtained from euhaploids. The evidence provided by the meiotic studies was used to identify chromosomes whose activities affected the genetic control of chromosome pairing.Meiosis was abnormal in a 23-chromosome aneuhaploid and in the 22-chromosome sectors of a chimaeral plant. Both plants were thought to have resulted from the incomplete elimination of the genome of H. bulbosum from hybrid embryos. It is suggested that the meiotic abnormalities in the two aneuhaploids were caused by the residual barley chromosomes.

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On the possible gamma-ray source in Cygnus

Symposium - International Astronomical Union ◽

10.1017/s0074180900101391 ◽

1967 ◽

Vol 31 ◽

pp. 469-471

Author(s):

J. G. Duthie ◽

M. P. Savedoff ◽

R. Cobb

Keyword(s):

Gamma Rays ◽

Gamma Ray ◽

Right Ascension

A source of gamma rays has been found at right ascension 20h15m, declination +35°, with an uncertainty of 6° in each coordinate. Its flux is (1·5 ± 0·8) x 10-4photons cm-2sec-1at 100 MeV. Possible identifications are reviewed, but no conclusion is reached. The mechanism producing the radiation is also uncertain.

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Solar Flare Energetic Neutral Emission Measurements in the Project Coronas-I

International Astronomical Union Colloquium ◽

10.1017/s0252921100026208 ◽

1994 ◽

Vol 144 ◽

pp. 635-639

Author(s):

J. Baláž ◽

A. V. Dmitriev ◽

M. A. Kovalevskaya ◽

K. Kudela ◽

S. N. Kuznetsov ◽

...

Keyword(s):

Solar Flare ◽

Energy Range ◽

Gamma Rays ◽

Pulse Shape ◽

Gamma Ray ◽

Pulse Shape Discrimination ◽

Shape Discrimination ◽

Solar Neutron ◽

Low Altitude

AbstractThe experiment SONG (SOlar Neutron and Gamma rays) for the low altitude satellite CORONAS-I is described. The instrument is capable to provide gamma-ray line and continuum detection in the energy range 0.1 – 100 MeV as well as detection of neutrons with energies above 30 MeV. As a by-product, the electrons in the range 11 – 108 MeV will be measured too. The pulse shape discrimination technique (PSD) is used.

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Ovarian Dysfunction in Fetally Irradiated Beagles

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100080717 ◽

1977 ◽

Vol 35 ◽

pp. 658-659

Author(s):

T. M. Seed ◽

M. H. Sanderson ◽

D. L. Gutzeit ◽

T. E. Fritz ◽

D. V. Tolle ◽

...

Keyword(s):

Gamma Rays ◽

Low Dose ◽

Long Term Effects ◽

Ovarian Dysfunction ◽

Dose Rates ◽

Highly Sensitive ◽

Microscopic Evaluation ◽

Ovarian Pathology ◽

Normal Offspring

The developing mammalian fetus is thought to be highly sensitive to ionizing radiation. However, dose, dose-rate relationships are not well established, especially the long term effects of protracted, low-dose exposure. A previous report (1) has indicated that bred beagle bitches exposed to daily doses of 5 to 35 R 60Co gamma rays throughout gestation can produce viable, seemingly normal offspring. Puppies irradiated in utero are distinguishable from controls only by their smaller size, dental abnormalities, and, in adulthood, by their inability to bear young.We report here our preliminary microscopic evaluation of ovarian pathology in young pups continuously irradiated throughout gestation at daily (22 h/day) dose rates of either 0.4, 1.0, 2.5, or 5.0 R/day of gamma rays from an attenuated 60Co source. Pups from non-irradiated bitches served as controls. Experimental animals were evaluated clinically and hematologically (control + 5.0 R/day pups) at regular intervals.

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