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from article Aquarius

Modern boundaries of the constellation Aquarius, the Water Bearer. The celestial equator is 0° of declination, which corresponds to celestial latitude. Right ascension corresponds to celestial longitude, with each hour of right ascension…

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from article Particle track etching

Upper images show increasing radiation damage produced by a high-energy uranium nucleus in the cosmic radiation as it penetrates a thick stack of Lexan plastic sheets and slows down. The lengths of the etched cones in these three sheets, taken at…

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from article Particle track etching

Etched conical pits in a sheet of allyl diglycol carbonate (CR-39 plastic) irradiated at normal incidence with 60-MeV alpha particles. (From P. B. Price et al., Do energetic heavy nuclei penetrate deeply into the Earth's atmosphere?, Proc. Nat.…

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from article Particle track etching

Etched fossil particle tracks. (a) Tracks from spontaneous fission of 238U and 244Pu in a zircon crystal from a lunar breccia, seen by scanning electron microscopy (from D. Braddy et al., Crystal chemistry of Pu and U and concordant fission track…

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from article Particle track etching

Reconstructed images of right and left breasts of a patient taken by using a 3600-MeV carbon-ion beam at the Lawrence Berkeley Laboratory Bevalac accelerator. Arrow indicates 1-cm (0.4-in.) carcinoma. (From C. A. Tobias et al., Lawrence Berkeley…

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from article Eclipsing variable star

Relative sizes and separation of components of R Canis Majoris. Shaded star represents cooler component. It is shown in two positions: at the middle of an eclipse and when separation would be greatest as viewed from Earth. Even at the greatest…

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from article Eclipsing variable star

Model generally accepted for certain types of eclipsing binary stars, in particular those known as dwarf novae.

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from article Neandertal DNA

The geographical range within which Neandertal remains have been found (dashed line). White dots show the sites of the discoveries used to estimate the almost-complete hypervariable segment I (HVS-I) sequence of the Neandertal mtDNA. The approximate…

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from article Neandertal DNA

The mtDNA hypervariable segment I (HVS-I) diversity found in eight Neandertals. The nucleotide substitutions and insertions relative to the Cambridge Reference Sequence (CRS) are shaded. (Credit: Igor Ovchinnikov and William Goodwin)

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from article Neandertal DNA

Phylogenetic analysis of the Neandertal mtDNA hypervariable segment I (HVS-I) sequence. (a) Neighbor-joining tree of the Neandertal mtDNA sequences and 2500 modern human HVS-I sequences from 43 modern populations. (b) Neighbor-joining tree of the…