sex ratio

(redirected from Gender ratio)
Also found in: Dictionary, Encyclopedia.

ratio

 [ra´she-o] (L.)
an expression of the quantity of one substance or entity in relation to that of another; the relationship between two quantities expressed as the quotient of one divided by the other.
A/D ratio adult versus developmental toxicity ratio; the ratio between the toxic effects of a substance on adults (humans or animals, especially pregnant females) and such effects on developing embryos or fetuses.
A-G ratio (albumin-globulin ratio) the ratio of albumin to globulin in blood serum, plasma, cerebrospinal fluid, or urine.
arm ratio a figure expressing the relation of the length of the longer arm of a mitotic chromosome to that of the shorter arm.
benefit-risk ratio a determination of the potential of a research study for positive effects on patients compared to the risks of doing harm.
cardiothoracic ratio on a chest radiograph, the ratio of the transverse diameter of the heart to the internal diameter of the chest at its widest point just above the dome of the diaphragm.
grid ratio a ratio comparing the height of lead lines in an x-ray grid to the distance between the lead strips.
inspiratory-expiratory ratio the ratio of the inspiratory time to the expiratory time during the breathing cycle. Normally, expiratory time will be longer than inspiratory time; if the inspiratory time is longer than the expiratory time, gas trapping may result.
lecithin/sphingomyelin ratio see lecithin-sphingomyelin ratio.
risk ratio relative risk.
sex ratio the proportion of one sex to the other; by tradition the number of males in a population to the number of females, usually stated as the number of males per 100 females.
signal-to-noise ratio the ratio between the amplitude of a signal being measured and that of the noise.
urea excretion ratio the ratio of the amount of urea in the urine excreted in one hour to the amount in 100 ml of blood. The normal ratio is 50.
zeta sedimentation ratio (ZSR) a measurement comparable to the erythrocyte sedimentation rate, except that it is unaffected by anemia. The packed-cell volume (zetacrit) of a blood specimens is calculated by centrifuging the specimen in a Zetafuge, a specially designed instrument that produces controlled cycles of compaction and dispersion and allows rouleaux to form and sediment rapidly. The zetacrit divided into the true hematocrit gives the zeta sedimentation ratio.

sex ra·ti·o

1. the ratio of male to female progeny at some specified stage of the life cycle, notably at conception (primary), at birth (secondary), or at any stage between birth and death (tertiary);
2. the ratio of the numbers of males to females affected by a particular disease or trait.
The ratio of males to females in a population, which in humans—without ‘culling'—hovers at 105–107:100

sex ra·ti·o

(seks rā'shē-ō)
1. The ratio of male to female progeny at some specified stage of the life cycle, notably at conception (primary), at birth (secondary), or at any stage between birth and death (tertiary).
2. The ratio of the numbers of males to females affected by a particular disease or trait.
Sex ratioclick for a larger image
Fig. 284 Sex ratio . The ratio of male to female progeny in humans.

sex ratio

the number of males in a group divided by the number of females, giving a value which is usually about 1.0. The ratio is controlled by the SEGREGATION of SEX CHROMOSOMES in the HETEROGAMETIC SEX during MEIOSIS (see SEX DETERMINATION). For example, in humans the situation is normally as shown in Fig. 284. In fact, in humans there are often slightly more males born than females (105:100 is typical) due either to preferential fertilization of eggs by Y-carrying sperm causing an unequal primary ratio or to preferential survival of males during GESTATION. Whatever the reason, the sex ratio at birth (the secondary ratio) becomes altered to about 1:1 at sexual maturity in natural circumstances, due to the slightly higher mortality of male children.
References in periodicals archive ?
There is a 50:50 gender ratio of entry-level petroleum engineers and a balanced talent pool at junior and mid-career levels in the company.
The mean age of the patients was 36.2 years, with a gender ratio of 60:40 (male:female).
These findings support the gender ratio hypothesis, which posits that simultaneous hermaphrodites make mating decisions based on potential fitness gains for each distinct mating event.
It has skewed India's 1.2 billion population's gender ratio, particularly in the western states of Haryana, Rajasthan, and Punjab.
Luckily for Turkey, the gender ratio in local administration is not recorded.
"The job of a promoter is not to attempt to create a 50-50 gender ratio at their shows, but rather to put on events that promote excellence in a way that both disregards the sex of the band members but also creates a welcoming atmosphere for everyone involved, both musicians and gig-attendees alike.
While at one hand the state government is struggling to improve the plummeting gender ratio and cracking down on ultrasound clinics, it has had no qualms about appointing a brand ambassador who By Manjeet Sehgal in Chandigarh centre jaye to doctor kahe ki bhag ja nahi to Anil Vij aa jayega ( I want to create such a situation that if someone approaches a doctor for a sex determination test, he would tell the person to run away as Anil Vij will be there)," he tweeted.
The gender ratio in 2-5-y-old geoducks was male biased relative to the 1:1 sex ratio observed in wild populations (P [much less than] 0.05), providing evidence for facultative protandric dioecy.
There was a higher prevalence of limb traumatic injuries in men than women in all age groups (Gender ratio M/F = 2.7) which is more significant in laceration and dislocation and less prominent in ligamentous injury subgroups.
The global natural gender ratio at birth is 1.6 boys for every girl born.
The gender ratio for centenarians fell from 828 women for every 100 men in 2002, to 588 women for every 100 men in 2012.