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We present a chemical composition analysis of 36 giant stars in the mildly metalpoor (<[Fe/H]> = -1.21) globular cluster M5 (NGC 5904). The analysis makes use of high resolution data acquired for 25 stars at the Keck I telescope, as well as a reanalysis of the high resolution spectra for 13 stars acquired for an earlier study at Lick Observatory. We employed two analysis techniques: one, adopting standard spectroscopic constraints, including setting the surface gravity from the ionization equilibrium of iron, and two, subsequent to investigating alternative approaches, adopting an analysis consistent with the non-LTE precepts as recently described by Thévenin & Idiart. The abundance ratios we derive for magnesium, silicon, calcium, scandium, titanium, vanadium, nickel, barium and europium in M5 show no significant abundance variations and the ratios are comparable to those of halo field stars. However, large variations are seen in the abundances of oxygen, sodium and aluminum, the elements that are sensitive to proton-capture nucleosynthesis. These variations are well-correlated with the CN bandstrength index S(3839). Surprisingly, in M5 the dependence of the abundance variations on log g is in the opposite sense to that discovered in M13 by the Lick-Texas group where the relationship provided strong evidence in support of the evolutionary scenario. The present analysis of M5 giants does not necessarily rule out an evolutionary scenario, but it provides no support for it either. In comparing the abundances of M5 and M4 (NGC 6121), another mildly metal-poor (<[Fe/H]> = -1.08) globular cluster, we find that silicon, aluminum, barium and lanthanum are overabundant in M4 with respect to what is seen in M5, confirming and expanding the results of previous studies. In comparing the abundances between these two clusters and others having comparable metallicities, we find that the anti-correlations observed in M5 are similar

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We present photometric and spectroscopic observations of supernova (SN) 2002cx, which reveal it to be unique among all observed type Ia supernovae (SNe Ia). SN 2002cx exhibits a SN 1991T-like premaximum spectrum, a SN 1991bg-like luminosity, and expansion velocities roughly half those of normal SNe Ia. Photometrically, SN 2002cx has a broad peak in the $R$ band and a plateau phase in the $I$ band, and slow late-time decline. The $(B - V)$ color evolution is nearly normal, but the $(V - R)$ and $(V - I)$ colors are very red. Early-time spectra of SN 2002cx evolve very quickly and are dominated by lines from Fe-group elements; features from intermediate-mass elements (Ca, S, Si) are weak or absent. Mysterious emission lines are observed around 7000 \AA\ at about 3 weeks after maximum brightness. The nebular spectrum of SN 2002cx is also unique, consisting of narrow iron and cobalt lines. The observations of SN 2002cx are inconsistent with the observed spectral/photometric sequence, and provide a major challenge to our understanding of SNe Ia. No existing theoretical model can successfully explain all observed aspects of SN 2002cx.Comment: 60 pages, 12 figures. A high resolution PostScript version is available at http://astro.berkeley.edu/~weidong/sn2002cx.p