interval

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interval,

in music, the difference in pitch between two tones. Intervals may be measured acoustically in terms of their vibration numbers. They are more generally named according to the number of steps they contain in the diatonic scale of the piano; e.g., from C to D is a second, C and D being the first two notes of the scale of C. The fourth, fifth, and octave are termed perfect intervals as they have a characteristic sonority quite unlike any other interval. An interval between two natural notes, neither note being a sharp or a flat, is a major interval; if it is reduced by a semitone, it becomes minor. If a perfect or a minor interval is made half a step smaller it is called diminished, and when half a step larger, augmented. An interval may also be expressed by means of the ratio of the frequencies of its two tones. For example, the octave may be expressed by the ratio 2:1 because its upper tone has a frequency twice that of its lower tone.

Interval

 

in music and acoustics, the correlation of two tones according to pitch, that is, the frequency of sound vibration. The lower tone of an interval is known as its foundation, the upper its top. Tones employed in succession form a melodic interval; when used simultaneously, a harmonic interval. Each interval is determined by the volume, or quantitative, magnitude—that is, the number of steps it comprises—and the tonal, or qualitative, magnitude—that is, the number of whole tones or semitones it contains. Intervals formed within the limits of an octave are called simple intervals, and larger ones are called compound intervals. The names of intervals indicate the number of steps each embraces: the tonal size of the intervals determines whether they are minor, major, perfect, augmented, or diminished.

The simple intervals are perfect unison, minor second (a half tone), major second (one tone), minor third (1½ tones), major third (two tones), perfect fourth (2½ tones), augmented fourth (three tones), diminished fifth (three tones), perfect fifth (3½ tones), minor sixth (four tones), major sixth (4½tones), minor seventh (five tones), major seventh (5½tones), and perfect octave (six tones).

Compound intervals are created by adding a simple interval to the octave. They retain the characteristics of the analogous simple intervals; thus, there are ninths, tenths, elevenths, twelfths, thirteenths, fourteenths, and fifteenths (two octaves). Wider intervals are called a second above (or below) two octaves, a third above two octaves, and so on.

The enumerated intervals are known also as fundamental, or diatonic, intervals. Diatonic intervals can be increased or diminished by raising or lowering the foundation or top of the interval one chromatic semitone. If, simultaneously, both steps of an interval are subjected to alteration by a chromatic semitone in different directions, a double-augmented interval results; if one step is altered by one chromatic tone a double-diminished interval is produced. All intervals changed through alteration are called chromatic intervals. Intervals that differ in the quantity of steps they contain but are alike in tonal makeup (sound) are considered enharmonically equal—for example, F to G sharp (an augmented second) and F to A flat (a minor third).

All harmonic intervals are divided into consonant and dissonant intervals. The consonant intervals are the perfect unison and the octave (perfect consonance), the perfect fourth and the perfect fifth (very good consonance), and minor and major thirds and sixths (imperfect consonance). The dissonant intervals are minor and major seconds, the augmented fourth, the diminished fifth, and minor and major sevenths. The transference of the tones of an interval, during which the foundation becomes the upper tone of the interval and the top its lower tone, is called inversion; a new interval results. In inversion all perfect intervals remain perfect, minor intervals become major, major become minor, augmented become diminished, diminished become augmented, double augmented become double diminished, and double diminished become double augmented.

V. A. VAKHROMEEV

interval

[′in·tər·vəl]
(acoustics)
The spacing in pitch or frequency between two sounds; the frequency interval is the ratio of the frequencies or the logarithm of this ratio.
(mathematics)
A set of numbers which consists of those numbers that are greater than one fixed number and less than another, and that may also include one or both of the end numbers.
(physics)
The time separating two events, or the distance between two objects.
(relativity)
In special relativity, the Lorentz invariant quantity c 2t)2-(Δ x)2-(Δ y)2-(Δ z)2, where c is the speed of light, Δ t is the difference in the time coordinates of two specified events, and Δ x, Δ y, and Δ z are differences in their x, y, and z coordinates, respectively.
In general relativity, a generalization of this concept, namely the sum over the indices μ and ν of gμν dx μ dx ν, where dx μand dx νare the differences in the x μand x νcoordinates of two specified neighboring events, and gμνis an element of the metric tensor.

interval

1. Music the difference of pitch between two notes, either sounded simultaneously (harmonic interval) or in succession as in a musical part (melodic interval). An interval is calculated by counting the (inclusive) number of notes of the diatonic scale between the two notes
2. the ratio of the frequencies of two sounds
3. Maths the set containing all real numbers or points between two given numbers or points, called the endpoints. A closed interval includes the endpoints, but an open interval does not
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These findings correspond to those who posited that the effect of long interpregnancy intervals is due to the fact that the protective effect that women might have acquired along the previous pregnancy is lost after a long interval (8,12,31).
Lesser the interpregnancy interval, more the risk of delivering LBW.
7) Women with interpregnancy intervals of less than 18 months appear to be at greater risk of having a premature birth or a low-birth-weight baby than women with longer intervals.
Interpregnancy interval and low birth weight: findings from case-control study.
But I think this data adds to the growing literature about the effect of interpregnancy interval and adverse perinatal outcomes, which we see again and again.
The significantly increased risk was not attenuated by adjustment for maternal age, height, smoking, status, social deprivation, and interpregnancy interval or for key outcomes of the first pregnancy, including birth weight percentile, preterm delivery, and perinatal death.
Using 12 months as a reference point, women who had an interpregnancy interval shorter than 6 months had triple the risk of uterine rupture.
Children born into families with short interpregnancy intervals are exposed to increased parenting stress and negative parenting behaviors.
One of the most important successes is postponing repeat pregnancies, because studies have shown an association between short interpregnancy intervals and poor birth outcomes (Khoshnood, Lee, Wall, Hseih, & Mittendorf, 1998; Rawlings, Rawlings, & Read, 1995) and higher risk of poor birth outcomes for second births to teenage mothers compared to alder mothers (Santelli & Jacobsen, 1990; Akinbami, Schoendorf, & Kiely, 2000).
The reasons for problems with interpregnancy intervals include inadequate time for the mother to restore her nutritional status and the stress associated with having a baby.
In the tricky Milanese case, interpregnancy intervals lengthened, which might suggest longer lactation replacing wetnursing except that protogenesic intervals lengthened as well: Dante E.