dispersion measure

dispersion measure

(DM) The number of electrons per unit volume, n e, integrated along the line of sight to a source:
DM = n e dl

where dl is an element of the path. It is the factor that determines, for example, the time delay (i.e. dispersion) between the arrival of radio pulses from a pulsar at two different frequencies. The value of n e in the plane of our Galaxy is typically 0.03 cm–3.

dispersion measure

[də′spər·zhən ‚mezh·ər]
(astronomy)
A quantity that describes the dispersion of a radio signal, proportional to the product of the density of interstellar electrons and the distance to the source.
References in periodicals archive ?
The residuals from those models, "purged" of such effects, are then used to construct price dispersion measures which are regressed on variables related to search costs.
Price dispersion measures computed directly from price data indicate that prices for pharmaceutical drugs vary substantially both within and between individual markets.
They employ measures based on stock prices to create a dispersion measure that reflects structural shifts rather than short-term cyclical fluctuations.
In his original paper, Lilien (1982) presented a dispersion measure as a way to quantify the degree of sectoral reallocation occurring in the economy at any given time.
The next investigation is of dispersion measures by gender to see if controlling for work experience, education, and occupation results in a more equal (less disperse) distribution of earnings between men and women.
The sum of job creation and destruction series such as those by Davis and Haltiwanger or those produced using industry data can be used as a cross-sectional dispersion measure.
Using data on job vacancies, Katherine Abraham and Lawrence Katz [1986] rebut Lilien's conclusion, claiming that the positive coefficient of his dispersion measure picks up the effects of aggregate demand rather than interindustry supply disturbances, and that, therefore, aggregate-demand expansion was the appropriate policy for reducing unemployment in the 1970s.
7% of the mean value, and the highest dispersion measure of any product.
One explanation is that the dispersion measures of linkage strategies used in the study are specified too generally.
Because change in business inventories is frequently negative, it is not possible to calculate percent changes or dispersion measures for this GDP component.
The 1999 Peer Administrative Expense Benchmarking Study - Blue Cross Blue Shield Plans Edition, provides ranges, dispersion measures and averages of administrative expenses by function and departments as well as by product line for eleven Blue Cross Blue Shield Plans.
The 1999 Peer Administrative Expense Benchmarking Study, Sherlock Company's second annual survey, provides ranges, dispersion measures and averages on five large health plans that are SEC registrants.