Results 11 to 20 of about 2,243,500 (299)
Widespread sex ratio polymorphism in Caenorhabditis nematodes
Royal Society Open Science, 2023 Although equal sex ratio is ubiquitous and represents an equilibrium in evolutionary theory, biased sex ratios are predicted for certain local conditions. Cases of sex ratio bias have been mostly reported for single species, but little is known about its
Yun Huang +7 more
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Recent sex ratio at birth in China
BMJ Global Health, 2021 Background China’s sex ratio at birth (SRB) has declined in the past decade but still exceeds the normal level. This study seeks to depict the SRB trend in the past two decades.Methods We depicted the SRB trend, including SRB by birth order, children ...
Quanbao Jiang, Cuiling Zhang
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Economic stress affects the human sex ratio: A retest of the Trivers–Willard hypothesis in Poland
Anthropological Review, 2023 This paper contributes to the verification of the Trivers–Willard hypothesis (TWH). Based on the TWH, observed sex (male-to-female) ratio at birth in a population is presumed to decline when parents experience economic stress.
Artur Mikulec +2 more
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Determinants of child sex ratio in West and South Districts of Tripura, India
Indian Journal of Public Health, 2017 Background: Indian census 2011 has detected declined child sex ratio in the West and South districts of Tripura State. Objectives: To find out the sex ratio at birth and to identify the factors affecting child sex ratio in west and south districts of ...
Himadri Bhattacharjya, Subrata Baidya
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Sex investment ratios in eusocial Hymenoptera support inclusive fitness theory [PDF]
, 2015 Inclusive fitness theory predicts that sex investment ratios in eusocial Hymenoptera are a function of the relatedness asymmetry (relative relatedness to females and males) of the individuals controlling sex allocation. In monogynous ants (with one queen
Bourke, Andrew F. G.
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Human sex ratio at amniocentesis and at birth in Taiwan
Taiwanese Journal of Obstetrics & Gynecology, 2012 Objectives: An increase in the proportion of male-to-female live births has raised concerns in Taiwan. Disclosure of fetal sex during prenatal screening is not allowed by the Taiwan government.
I-Wen Lee +3 more
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Reproduction, 1968 The slight excess of male births in most mammals reflects the interplay of two factors, the primary sex ratio at fertilization and the possible existence of a sex difference in pre-natal mortality. Among the explanations of this putative departure of the primary sex ratio from unity is that spermatozoa bearing the smaller Y-chromosome are more motile ...
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Sex ratio elasticity influences the selection of sex ratio strategy [PDF]
Scientific Reports, 2016 There are three sex ratio strategies (SRS) in nature—male-biased sex ratio, female-biased sex ratio and, equal sex ratio depending on the proportion of male offspring being greater than, less than, or equal to ½. The problem was already noted in Darwin’s (1859) “Origin of Species,” and it was R. A.
Wang, Yaqiang +3 more
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Climate influences fledgling sex ratio and sex-specific dispersal in a seabird. [PDF]
PLoS ONE, 2013 Climate influences the dynamics of natural populations by direct effects over habitat quality but also modulating the phenotypic responses of organisms' life-history traits. These responses may be different in males and females, particularly in dimorphic
Alvaro Barros +2 more
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EVALUATION OF SEMEN SEX RATIO IN COOLED AND FROZEN SEMEN STRAWS BY REAL-TIME PCR [PDF]
Basrah Journal of Veterinary Research, 2016 The study was demonstrated on quantitative evaluation of SRY and ZFX gene of (120) semenstraws from 10 Holliston bull (60) straws in cooling state 5C° and 60 straws after deep freezingin liquid nitrogen) .
Baqer Ja’fer. Hassan +2 more
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