منابع مشابه
Inferring the global cosmic dust influx to the Earths atmosphere from lidar observations of the vertical flux of mesospheric Na
Estimates of the global influx of cosmic dust are highly uncertain, ranging from 0.4–110 t/d. All meteoric debris that enters the Earth’s atmosphere is eventually transported to the surface. The downward fluxes of meteoric metals like mesospheric Na and Fe, in the region below where they are vaporized and where the majority of these species are still in atomic form, are equal to their meteoric ...
متن کاملThe two earths of Eratosthenes.
In the third century B.C.E., Eratosthenes of Cyrene made a famous measurement of the circumference of the Earth. This was not the first such measurement, but it is the earliest for which significant details are preserved. Cleomedes gives a short account of Eratosthenes' method, his numerical assumptions, and the final result of 250,000 stades. However, many ancient sources attribute to Eratosth...
متن کاملthe effect of taftan pozzolan on the compressive strength of concrete in the environmental conditions of oman sea (chabahar port)
cement is an essential ingredient in the concrete buildings. for production of cement considerable amount of fossil fuel and electrical energy is consumed. on the other hand for generating one tone of portland cement, nearly one ton of carbon dioxide is released. it shows that 7 percent of the total released carbon dioxide in the world relates to the cement industry. considering ecological issu...
Justice and Peaceful Cooperation
Justice is important, but so is peaceful cooperation. In this article, I argue that if one takes seriously the autonomy of individuals and groups and the fact of moral pluralism, a just system of cooperation cannot guarantee peaceful cooperation in a pluralistic world. As a response to this consideration, I develop a contractarian theory that can secure peaceful cooperation in a pluralistic wor...
متن کاملPeaceful collaborations deserve support.
THE FORMER RAND AFRIKAANS UNIVERSITY, now University of Johannesburg, has acted against its own and the South African national interest by terminating the 25-year-old collaboration with the Ben Gurion University of the Negev (Around the World item “End to partnership with Israeli university,” News of the Week, 1 April, p. 19). Boycotts of Israeli scientists, science institutions, and worse, res...
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ژورنال
عنوان ژورنال: Science
سال: 1966
ISSN: 0036-8075,1095-9203
DOI: 10.1126/science.152.3719.159