A true bronchial dosimeter has been designed, consisting of four 400-mesh wire screens and a filter paper. With a face velocity of 3.3 cm s(-1) for home exposure and 4.6 cm s(-1) for mine exposure, the deposition pattern on the wire screens were found to satisfactorily match the variation of the dose conversion factor (in units of mSv WL M(-1)) with the size of radon progeny from 1 to 1000 nm. ...

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A new type of hybrid sterility was investigated in D. melanogaster . Matings between strain 27 males from Para Wirra, South Australia, and Canton-S females produce 70-80% fully sterile male and female progeny. Strain 27 males produce sterile progeny when crossed to females of other geographic origins, but produce fertile progeny when crossed to a second sympatric strain. The sterility is avoide...

Inhalation of Rn progeny has been recognized as a health risk, primarily as a cause of human lung cancer. Rn progeny in the domestic environment contributes the greatest fraction of the natural radiation exposure to the public. The ultrafine activity of these progeny amounts up to about 10 percent of the total activity (attached and ultrafine), but is considered to yield about 50 percent of the...

Dimorphic cleistogamy is a specialized form of mixed mating system where a single plant produces both open, potentially outcrossed chasmogamous (CH) and closed, obligately self-pollinated cleistogamous (CL) flowers. Typically, CH flowers and seeds are bigger and energetically more costly than those of CL. Although the effects of inbreeding and floral dimorphism are critical to understanding the...

Programmed excision of internal eliminated sequences (IESs) occurs at thousands of sites in ciliate genomes. How this is controlled is largely unknown. Here, we report the characterization of the non-efficiently excised 156psiG-11 IES from Paramecium primaurelia strain 156 and that of the efficiently excised 168psiG-11 IES, an allelic variant from strain 168. Then, we report a genetic and molec...