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We present detailed analyses of the absorption spectrum seen in QSO 2359-1241. Keck HIRES data reveal absorption from twenty transitions arising from: He i, Mg i, Mg ii, Ca ii, and Fe ii. HST data show broad absorption lines (BALs) from Al iii λ1857, C iv λ1549, Si iv λ1397, and N v λ1240. Absorption from excited Fe ii states constrains the temperature of the absorber to 2000 < ∼ T < ∼ 10, 000 K and puts a lower limit of 10 5 cm −3 on the electron number density. Saturation diagnostics show that the real column densities of He i and Fe ii can be determined, allowing to derive meaningful constraints on the ionization equilibrium and abundances in the flow. The ionization parameter is constrained by the iron, helium and magnesium data to −3.0 < ∼ log(U) < ∼ −2.5 and the observed column densities can be reproduced without assuming departure from solar abundances. From comparison of the He i and Fe ii absorption features we infer that the outflow seen in QSO 2359-1241 is not shielded by a hydrogen ionization front and therefore that the existence of low-ionization species in the outflow (e.g., Mg ii, Al iii, Fe ii) does not necessitate the existence of such a front. We find that the velocity width of the absorption systematically increases as a function of ionization and to a lesser extent with abundance. Complementary analyses of the radio and polarization properties of the object are discussed in a companion paper (Brotherton et al. 2000).

We have obtained single-epoch optical photometry for 201 quasars, taken from the FIRST Bright Quasar Survey, which span a wide range in radio loudness. Comparison with the magnitudes of these objects on the POSS-I plates provides by far the largest sample of long-term variability amplitudes for radio-selected quasars yet produced. We find the quasars to be more variable in the blue than in the red band, consistent with work on optically selected samples. The previously noted trend of decreasing variability with increasing optical luminosity applies only to radio-quiet objects. Furthermore, we do not confirm a rise in variability amplitude with redshift, nor do we see any dependence on radio flux or luminosity. The variability over a radio-optical flux ratio range spanning a factor of 60,000 from radio-quiet to extreme radio-loud objects is largely constant, although there is a suggestion of greater variability in the extreme radio-loud objects. We demonstrate the importance of Malmquist bias in variability studies, and develop a procedure to correct for the bias in order to reveal the underlying variability properties of the sample.

Catalytic conversion of alcohols underlies many commodity and fine chemical syntheses, but a complete mechanistic understanding is lacking. We examined catalytic oxidative conversion of methanol near atmospheric pressure using operando small-aperture molecular beam timeof-flight mass spectrometry, interrogating the gas phase 500 μm above Pdbased catalyst surfaces. In addition to a variety of stable C 1−3 species, we detected methoxymethanol (CH 3 OCH 2 OH)a rarely observed and reactive C 2 oxygenate that has been proposed to be a critical intermediate in methyl formate production. Methoxymethanol is observed above Pd, Au x Pd y alloys, and oxide-supported Pd (common methanol oxidation catalysts). Experiments establish temperature and reactant feed ratio dependences of methoxymethanol generation, and calculations using density functional theory are used to examine the energetics of its likely formation pathway. These results suggest that future development of catalysts and microkinetic models for methanol oxidation should be augmented and constrained to accommodate the formation, desorption, adsorption, and surface reactions involving methoxymethanol.