This study explores the relation of the human sex ratio at birth to four selected variables: calendar-year, color, maternal age, and parity of mother. In the analysis of variance, the sex ratio at birth is found to differ significantly by color, age of mother, and birth order of child....
Focuses on the quaking aspen plant which is the most colorful plant in the fall in western United States and Canada. How the quaking aspen got its name; Sp... JB Mitton,MC Grant - 《Bioscience》 被引量: 610发表: 1996年 Alternative Concepts of Reproductive Effort, Costs of Reproduction,...
Sex ratio theory predicts that, if prevailing ecological or social circumstances differentially influence the fitness benefits of offspring of each sex, pa... R. G. NAGER, P. MONAGHAN,R Griffiths,D. C. HOUSTON - 《Proceedings of the National Academy of Sciences of the United States of America...
The observed ratio of older brothers to older sisters was 105 for the heterosexual right-handers, 128 for the homosexualright-handers, 127 for the heterosexual non-right-handers, and 96 for the homosexual non-right-handers. The ratios for thehomosexual right-handers and the 展开 ...
Paternal effects on the human sex ratio at birth: evidence from interracial crosses. The effects of interracial crossing on the human sex ratio at birth were investigated using United States birth-certificate data for 1972-1979. The sex rat... MJ Khoury,JD Erickson,LM James - 《American Journa...
It is concluded that the lack of sex-ratio and gender differences is explained best by the fact that the present methodology eliminated face-to-face interviews, which may expose males to greater negative repercussions for exhibiting depressed behavior. 展开 ...
In , dams that conceive in their postpartum oestrus and then lose their firstborn litter bias the sex ratio of the litter toward females in utero. The present study identifies the source of litter sex ratio bias in these postpartum pregnant non-lactating dams. The female bias arises first th...
Women with greater awareness of sexual consent were significantly more likely to report a history of forced sex (odds ratio [OR] = 1.553,p< .000, CI [1.324, 1.820]), and women who utilized more nonverbal, indirect approaches to sexual consent negotiation were less likely to report a ...
Werren and Charnov (1978) and Seger (1983) proposed a model to explain a fairly common pattern of alternating sex ratio biases between generations in partially bivoltine insects. When first-generation males overlap and mate with females of the second generation, then females should bias sex ratio...
Studies the relationships between offspring sex ratio and the size of a male secondary sexual character involved in female choice in a natural population o... Ellegren,Hans,Gustafsson,... - 《Proceedings of the National Academy of Sciences of the United States of America》 被引量: 642发表: ...