RESUMO
Aedes aegypti developed a taste for humans at the birth of the Sahara, a new analysis suggests.
Assuntos
Aedes , Evolução Biológica , Mosquitos Vetores , Febre Amarela , Animais , Humanos , Aedes/fisiologia , Aedes/virologia , África do Norte , Febre Amarela/parasitologia , Febre Amarela/transmissão , Paladar , Mosquitos Vetores/fisiologia , Mosquitos Vetores/virologia , Mordeduras e Picadas/virologiaRESUMO
The historic Maya oriented their lives by the heavens. Today, their descendants and Western scholars team up to understand their sophisticated astronomy.
RESUMO
City lights lure migratory birds, with lethal results, but weather radar and modeling can help reduce the toll.
Assuntos
Migração Animal , Aves , Animais , Cidades , Radar , Tempo (Meteorologia)RESUMO
Gravitational deflection of starlight around the Sun during the 1919 total solar eclipse provided measurements that confirmed Einstein's general theory of relativity. We have used the Hubble Space Telescope to measure the analogous process of astrometric microlensing caused by a nearby star, the white dwarf Stein 2051 B. As Stein 2051 B passed closely in front of a background star, the background star's position was deflected. Measurement of this deflection at multiple epochs allowed us to determine the mass of Stein 2051 B-the sixth-nearest white dwarf to the Sun-as 0.675 ± 0.051 solar masses. This mass determination provides confirmation of the physics of degenerate matter and lends support to white dwarf evolutionary theory.