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With increasing altitude, solar UV-B radiation is enhanced. Based on the phenomenon of male-biased sex ratio of Populus cathayana Rehder in high altitude alpine area, we hypothesized that males have a faster and more sophisticated responsive mechanism to high UV-B radiation than that of females. Our previous studies have shown sexually different responses to high UV-B radiation were existed in P.
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Sexual reproduction is a type of life cycle where generations alternate between cells with a single set of chromosomes haploid and cells with a double set of chromosomes diploid. Diploid cells divide into haploid cells in a process called meiosis. Two haploid cells combine into one diploid cell in a process called fertilisation. Between fertilisation and meiosis there can be multiple cell divisions without change of the number of chromosomes.
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UV light is important for reptile health. Sunshine is one way for them to get it. Ultraviolet UV light is a part of the light spectrum the whole range of light wavelengths that is invisible to humans.
Cystic fibrosis CF and short bowel syndrome SBS patients are unable to absorb vitamin D from the diet and thus are frequently found to be severely vitamin D deficient. We evaluated whether a commercial portable ultraviolet UV indoor tanning lamp that has a spectral output that mimics natural sunlight could raise circulating hydroxyvitamin D [25 OH D] levels in subjects with CF and SBS. In initial pilot studies, two SBS subjects came to the outpatient clinic twice weekly for 8 weeks for UV light sessions of 6 min each. In a follow-up study, five CF subjects exposed their lower backs in a seated position to the sunlamp at a distance of 14 cm for 5—10 min depending on the skin type five times a week for 8 weeks.