Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Extremely Metal-Poor Stars. VIII. High-Resolution, High-Signal-To-Noise
  Analysis of Five Stars with [Fe/H] < -3.5   High-resolution, high-signal-to-noise (<S/N> = 85) spectra have been obtained
for five stars -- CD-24:17504, CD-38:245, CS 22172-002, CS 22885-096, and CS
22949-037 -- having [Fe/H] < -3.5 according to previous lower S/N material. LTE
model-atmosphere techniques are used to determine [Fe/H] and relative
abundances, or their limits, for some 18 elements, and to constrain more
tightly the early enrichment history of the Galaxy than is possible based on
previous analyses.
  We compare our results with high-quality higher-abundance literature data for
other metal-poor stars and with the canonical Galactic chemical enrichment
results of Timmes et al. (1995) and obtain the following basic results: (1)
Large supersolar values of [C/Fe] and [N/Fe], not predicted by the canonical
models, exist at lowest abundance. For C at least, the result is difficult to
attribute to internal mixing effects; (2) We confirm that there is {\it no
upward trend} in [$\alpha$/Fe] as a function of [Fe/H], in contradistinction to
some reports of the behavior of [O/Fe]; (3) The abundances of aluminum, after
correction for non-LTE effects, are in fair accord with theoretical prediction;
(4) We confirm earlier results concerning the Fe-peak elements that [Cr/Fe] and
[Mn/Fe] decrease at lowest abundance, while [Co/Fe] increases -- behaviors that
had not been predicted. We find, however, that [Ni/Fe] does not vary with
[Fe/H], and at [Fe/H] ~ -3.7, [Ni/Fe] = +0.08 +/- 0.06. This result appears to
be inconsistent with the supernova models of Nakamura et al. (1999) that seek
to understand the observed behavior of the Fe-peak elements by varying the
position of the model mass cut relative to the Si-burning regions.
(abbreviated)

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The categories of this paper are: adap-org
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The categories of this paper are: plasm-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: q-bio
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The categories of this paper are: supr-con
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The categories of this paper are: nlin
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The categories of this paper are: chao-dyn
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The categories of this paper are: funct-an
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The categories of this paper are: comp-gas
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The categories of this paper are: dg-ga
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The categories of this paper are: q-fin
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The categories of this paper are: mtrl-th
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The categories of this paper are: eess
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The categories of this paper are: econ
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The categories of this paper are: bayes-an
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The categories of this paper are: q-alg