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1. Music
a. not sharp or flat
b. denoting a note that is neither sharp nor flat
c. (of a key or scale) containing no sharps or flats
2. Music of or relating to a trumpet, horn, etc., without valves or keys, on which only notes of the harmonic series of the keynote can be obtained
3. Cards
a. (of a card) not a joker or wild card
b. (of a canasta or sequence) containing no wild cards
c. (of a bid in bridge) describing genuine values; not conventional
4. based on the principles and findings of human reason and what is to be learned of God from nature rather than on revelation
5. Music
a. an accidental cancelling a previous sharp or flat.
b. a note affected by this accidental
6. Pontoon the combination of an ace with a ten or court card when dealt to a player as his or her first two cards

tropical year

tropical yearclick for a larger image
The period between two successive vernal equinoxes, the time the earth takes to complete one orbit around the sun relative to the first point of Aries. Its length was 365 days 5 h 48 min and 45.19 s in 2000, and it is changing by 0.00000006162 x y days (y in Julian years from 2000), or about 5 milliseconds/year. The tropical year differs from the solar year by 1 part in 26,000, since this is the period of the earth's precession about its rotational axis combined with the precession of the perihelion of the earth's orbit. Also called an astronomical, equinoctial, natural, or solar year. It contains one complete cycle of seasons.


An integrated 4GL from Software AG, Germany. The menu-driven version is SUPER/NATURAL.

Natural 2 is a major upgrade to Natural 1.

Version 2.1.7 in the MVS environment (June 1995, also available for Unix).

Natural works with DB2 and various other databases, but Natural and Adabas normally go together. There are many products available in the "Natural" family, including SuperNatural, Natural for Windows, Entire Connection (enables up/downloading and interaction with Excel) and Esperant.


An earlier fourth-generation language from Software AG, Reston, VA, that ran on a variety of computers from micro to mainframe. See fourth-generation language.
References in periodicals archive ?
In a natural experiment research design, qualitative pieces of evidence can also help to bolster (or invalidate) the contention that assignment to treatment is as-if random.
In the empirical part, I apply the assessment algorithm to five examples of natural experiments from modern Political Science.
The book is not a systematic examination of history's natural experiments, as the title might lead one to expect, and, annoyingly, it lacks an index.
Therefore, it has been decided to restrict the meta-analysis to four randomised controlled experiments and the one natural experiment whose internal validity seems beyond doubt.
We considered 2 subgroups of eligible studies separately: the RCTs and CCTs or natural experiments that had nonherbal/ Ayurvedic comparison arm(s) were considered 1 subgroup, and all other eligible (pre/post data available) studies made up the second subgroup.
Results from explicit natural experiments using cross-sectional data on five major tax reforms since 1920 are then presented.
I used natural experiments to examine patterns of grasshopper and plant abundances in relation to structures that naturally housed lizards and those that had none.
Methodology aside, Card and Krueger's empirical results suggest strong and, in some cases, surprising conclusions: negligible employment effects in most cases, and positive employment effects in some well-designed natural experiments.
In this study, four natural experiments are used to examine the effect of two Workers' Compensation policy changes--an increase in the dollar amount of income replacement benefits and a change in the rules used to determine the amount of compensation--on the duration of work absence following an injury that produces a permanent impairment.
18 Natural Experiments as a Means of Testing Causal Inferences

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