length

(redirected from cervical length)
Also found in: Dictionary, Thesaurus, Medical, Legal, Wikipedia.

length

1. Prosody Phonetics the metrical quantity or temporal duration of a vowel or syllable
2. the distance from one end of a rectangular swimming bath to the other
3. Prosody the quality of a vowel, whether stressed or unstressed, that distinguishes it from another vowel of similar articulatory characteristics. Thus in English beat is of greater length than in English bit
4. Cricket the distance from the batsman at which the ball pitches
5. Bridge a holding of four or more cards in a suit

Length

A one-dimensional extension in space. Length is one of the three fundamental physical quantities, the others being mass and time. It can be measured by comparison with an arbitrary standard; the specific one in most common usage is the international meter. In 1983, at the meeting of the Conférence Général des Poids et Mésures, the meter was redefined in terms of time and the speed of light: “The meter is the length of the path traveled by light in vacuum during a time interval of 1/299 792 458 of a second.” This definition defines the speed of light to be exactly 299 792 458 m/s, and defines the meter in terms of the most accurately known quantity, the second. See Light, Mass, Time

Length

 

a numerical characteristic of the extent of curves. The concept of length is defined differently for different cases. (1) The length of a line segment is the distance between its end points, measured by some segment taken as a unit of length. (2) The length of a polygonal line is the sum of the lengths of its components. (3) The length of a simple arc is the limit of the lengths of polygonal lines inscribed in the arc, when the number of components increases indefinitely and the maximum length of the components tends to zero. (4) The length of a continuous curve consisting of a finite number of simple arcs is equal to the sum of the lengths of these arcs. For example, the circumference of a circle can be obtained as the limit of the perimeters of inscribed regular polygons when the number of their sides is doubled indefinitely; it is equal to 2πR where R is the radius of the circle. Any continuous curve has finite or infinite length. If its length is finite, then the curve is said to be rectifiable. The graph (see Figure 1) of the function

for 0 <x ≤ 1 and f(x) = 0 when x = 0 is an example of a nonrectifiable curve; here the lengths of the inscribed polygonal lines increase beyond all bound as the length of the components tend to zero. If the equation of a plane curve has the form y =f(x) (a ^ x ^ b)m rectangular coordinates and the function f(x) has a continuous derivative f’(x), then the length of the curve is given by the integral

The length of a curve given in parametric form and the length of a space curve can be expressed in a similar manner.

Figure 1

To calculate the length of a curve the mathematicians of antiquity essentially used lengths of polygonal lines and passage to the limit. For them, however, such passage to the limit was only a method for calculating the length of a curve and not for defining the concept of the length of a curve, since they apparently perceived the latter as one of the elementary mathematical concepts. The necessity of defining the length of a curve became clear only in the first half of the 19th century. A full elucidation of the problem was achieved by C. Jordan. In differential geometry the length of a curve is also defined on a surface or in an arbitrary Riemannian space.

REFERENCES

Lebesgue, H. Ob izmerenii velichin, 2nd ed. Moscow, 1960. (Translated from French.)
Fikhtengol’ts, G. M. Kurs differentsial’nogo i integral’nogo ischisleniya, 7th ed. vol. 2. Moscow, 1969.

length

[leŋkth]
(mechanics)
Extension in space.
References in periodicals archive ?
The study enrolled 458 asymptomatic women with cervical length of 10-20 mm at 19-23 weeks' gestation.
The Cleveland-based company is commercializing a patented, Federal Drug Administration cleared medical device that allows obstetricians to easily measure cervical length in pregnant women, which has been established by the National Institutes of Health as an effective predictor of preterm birth risk.
Using a cervical length cutoff of the 10th percentile potentially expands the benefits of progesterone to a larger proportion of the population," said Dr.
We analyzed five variables: sex, previous fibroscopy, cervical length (<5 cm, 5.
Such studies (39-41) led to the more recent ACOG Practice Bulletin in 2012 recognizing the utility of routine second trimester cervical length evaluation even in low risk populations.
Seminal studies of transvaginal sonography to measure cervical length during pregnancy and predict premature birth were published more than 2 decades ago.
The study concluded: "CerviLenz may be an evidence-based method supporting universal cervical length screening in clinical practice.
Transvaginal ultrasound (TVS) can be used as an objective and reproducible method to measure cervical length throughout pregnancy.
Werner said: "Since only 10 percent of preterm birth occurs in women with a history of preterm birth, cervical length screening may be the best way to decrease the number of babies born prematurely.
From the very beginning of my second pregnancy I began having my cervical length monitored and was given progesterone shots to sustain the pregnancy for as long as possible.
Contraindications included undiagnosed uterine bleeding, pregnancy or the desire to become pregnant, atypical endometrial cells, cervical length more than 6 mm, a uterine cavity less than 4 cm or more than 10 cm, uterine wall weakness, and ongoing infection.
Food and Drug Administration (FDA) has denied Watson Pharmaceuticals' (NYSE:WPI) Formal Dispute Resolution Request (FDRR) related to its New Drug Application (NDA 22-139) for Prochieve for the prevention of preterm birth in women with a short cervical length.

Full browser ?