Meteorites from Botswana

Martian surface paleotemperatures from thermochronology of meteorites.

The temporal evolution of past martian surface temperatures is poorly known. We used thermochronology and published noble gas and petrographic data to constrain the temperature histories of the nakhlites and martian meteorite ALH84001. We found that the nakhlites have not been heated to more than 350 degrees C since they formed. Our calculations also suggest that for most of the past 4 billion ...

Meteorites: Messengers from the Outer Space

Milhares de meteoróides, corpos sólidos do espaço extra-terrestre, entram na atmosfera da Terra a cada ano. São pedaços de rocha, metal ou aglomerados de rocha e metal, variando em massa de frações de grama a centenas de quilogramas. Aqueles que sobrevivem à passagem através da atmosfera e caem na Terra, são chamados meteoritos. Os meteoritos são as rochas primitivas, tão antigas quanto o Siste...

Terrestrial Ages of Some Meteorites from Oman

Meteorites: messengers from the early solar system.

Meteorites are fragments from solar system bodies, dominantly asteroids. A small fraction is derived from the Moon and from Mars. These rocks tell a rich history of the early solar system and range from solids little changed since the earliest phases of solid matter condensation in the solar nebula (chondrites) to material representing asteroidal metamorphism and melting, impact processes on th...

Routine HIV testing: a view from Botswana.

ollowing an announcement in October 2003 by President Festus Mogae, routine testing for HIV (RHT) was introduced in Botswana in January 2004. It was assumed that RHT would reduce the stigma associated with the "exclusivity" of HIV testing, enable earlier testing, allow more timely access to treatment, and ultimately reduce the rate of infection.1-3 Botswana's first year of RHT has shown an incr...