34 research outputs found
Worldwide Use and Impact of the NASA Astrophysics Data System Digital Library
By combining data from the text, citation, and reference databases with data
from the ADS readership logs we have been able to create Second Order
Bibliometric Operators, a customizable class of collaborative filters which
permits substantially improved accuracy in literature queries.
Using the ADS usage logs along with membership statistics from the
International Astronomical Union and data on the population and gross domestic
product (GDP) we develop an accurate model for world-wide basic research where
the number of scientists in a country is proportional to the GDP of that
country, and the amount of basic research done by a country is proportional to
the number of scientists in that country times that country's per capita GDP.
We introduce the concept of utility time to measure the impact of the
ADS/URANIA and the electronic astronomical library on astronomical research. We
find that in 2002 it amounted to the equivalent of 736 FTE researchers, or $250
Million, or the astronomical research done in France.
Subject headings: digital libraries; bibliometrics; sociology of science;
information retrievalComment: ADS bibcode: 2005JASIS..56...36K This is a portion (The bibliometric
properties of article readership information is the other part) of the
article: The NASA Astrophysics Data System: Sociology, bibliometrics and
impact, which went on-line in the summer of 200
Estimations of changes of the Sun's mass and the gravitation constant from the modern observations of planets and spacecraft
More than 635 000 positional observations (mostly radiotechnical) of planets
and spacecraft (1961-2010), have been used for estimating possible changes of
the gravitation constant, the solar mass, and semi-major axes of planets, as
well as the value of the astronomical unit, related to them. The analysis of
the observations has been performed on the basis of the EPM2010 ephemerides of
IAA RAS in post-newtonian approximation. The obtained results indicate on
decrease in the heliocentric gravitation constant per year at the level The positive secular
changes of semi-major axes have been obtained simultaneously
for the planets Mercury, Venus, Mars, Jupiter, Saturn, as expected if the
geliocentric gravitation constant is decreasing in century wise. The change of
the mass of the Sun due to the solar radiation and the solar wind and
the matter dropping on the Sun (comets, meteors, asteroids and dust) was
estimated. Taking into account the maximal limits of the possible
change, the value falls within the interval in year with the 95% probability. The
astronomical unit (au) is only connected with the geliocentric gravitation
constant by its definition. In the future, the connection between
and au should be fixed at the certain time moment, as it is inconvenient highly
to have the changing value of the astronomical unit.Comment: 20 pages, 4 tables, accepted for publication in Solar System
Research, 2011 (Astronomicheskii vestnik
The be phenomenon in early-type stars Abstracts
Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai