Food habits of Steller sea lions (Eumetopias jubatus) off Oregon and northern California, 1986–2007

We described the diet of the eastern stock of Steller sea lions (Eumetopias jubatus) from 1416 scat samples collected from five sites in Oregon and northern California from 1986 through 2007. A total of 47 prey types from 30 families were identified. The most common prey was Pacific hake (Merluccius productus), followed by salmonids (Oncorhynchus spp.), skates (Rajidae), Pacific lamprey (Lampetra tridentata), herrings (Clupeidae), rockfish (Sebastes spp.), and northern anchovy (Engraulis mordax). Steller sea lion diet composition varied seasonally, annually, and spatially. Hake and salmonids were the most commonly identified prey in scats collected during the summer (breeding season), whereas hake and skate were most common in the nonbreeding season. Continued research on Steller sea lion diet and foraging behavior in the southern extent of their range is necessary to address issues such as climate change, interaction with competing California sea lions, and predation impacts on valuable or sensitive fish stocks

Mixed valency in cerium oxide crystallographic phases: Determination of valence of the different cerium sites by the bond valence method

We have applied the bond valence method to cerium oxides to determine the oxidation states of the Ce ion at the various site symmetries of the crystals. The crystals studied include cerium dioxide and the two sesquioxides along with some selected intermediate phases which are crystallographically well characterized. Our results indicate that cerium dioxide has a mixed-valence ground state with an f-electron population on the Ce site of 0.27 while both the A- and C-sesquioxides have a nearly pure f^1 configuration. The Ce sites in most of the intermediate oxides have non-integral valences. Furthermore, many of these valences are different from the values predicted from a naive consideration of the stoichiometric valence of the compound

Doppler follow-up of OGLE transiting companions in the Galactic bulge

Two years ago, the OGLE-III survey (Optical Gravitational Lensing Experiment) announced the detection of 54 short period multi-transiting objects in the Galactic bulge (Udalski et al., 2002a, 2002b). Some of these objects were considered to be potential hot Jupiters. In order to determine the true nature of these objects and to characterize their actual mass, we conducted a radial velocity follow-up of 18 of the smallest transiting candidates. We describe here our procedure and report the characterization of 8 low mass star transiting companions, 2 grazing eclipsing binaries, 2 triple systems, 1 confirmed exoplanet (OGLE-TR-56b), 1 possible exoplanet (OGLE-TR-10b), 1 clear false positive and 3 unsolved cases. The variety of cases encountered in our follow-up covers a large part of the possible scenarii occuring in the search for planetary transits. As a by-product, our program yields precise masses and radii of low mass stars.Comment: accepted in A&

Probing populations of red giants in the galactic disk with CoRoT

The detection with CoRoT of solar-like oscillations in nearly 800 red giants in the first 150-days long observational run paves the way for detailed studies of populations of galactic-disk red giants. We investigate which information on the observed population can be recovered by the distribution of the observed seismic constraints: the frequency of maximum oscillation power (nu_max) and the large frequency separation (Deltanu). We propose to use the observed distribution of nu_max and of Deltanu as a tool for investigating the properties of galactic red-giant stars through comparison with simulated distributions based on synthetic stellar populations. We can clearly identify the bulk of the red giants observed by CoRoT as red-clump stars, i.e. post-flash core-He-burning stars. The distribution of nu_max and of Deltanu gives us access to the distribution of the stellar radius and mass, and thus represent a most promising probe of the age and star formation rate of the disk, and of the mass-loss rate during the red-giant branch. CoRoT observations are supplying seismic constraints for the most populated class of He-burning stars in the galactic disk. This opens a new access gate to probing the properties of red-giant stars that, coupled with classical observations, promises to extend our knowledge of these advanced phases of stellar evolution and to add relevant constraints to models of composite stellar populations in the Galaxy.Comment: 4 pages, 6 figures, accepted in A&A Letter

Globalisation, neo-liberalism and vocational learning: the case of English further education colleges

Further education (FE) has traditionally been a rather unspectacular activity. Lacking the visibility of schools or the prestige of universities, for the vast majority of its existence FE has had a relatively low profile on the margins of English education. Over recent years this situation has altered significantly and further education has undergone profound change. This paper argues that a combination of related factors – neo-liberalism, globalisation, and dominant discourses of the knowledge economy – has acted in synergy to transform FE into a highly performative and marketised sector. Against this backdrop, further education has been assigned a particular role based upon certain narrow and instrumental understandings of skill, employment and economic competitiveness. The paper argues that, although it has always been predominantly working class in nature, FE is now, more than ever, positioned firmly at the lower end of the institutional hierarchy in the highly class-stratified terrain of English education

An HST/ACS View of the Inhomogeneous Outer Halo of M31

We present a high precision photometric view of the stellar populations in the outer halo of M31, using data taken with the Hubble Space Telescope Advanced Camera for Surveys (HST/ACS). We analyse the field populations adjacent to 11 luminous globular clusters which sample the galactocentric radial range 18 < R < 100 kpc and reach a photometric depth of ~2.5 magnitudes below the horizontal branch (m_F814W ~27 mag). The colour-magnitude diagrams (CMDs) are well populated out to ~60 kpc and exhibit relatively metal-rich red giant branches, with the densest fields also showing evidence for prominent red clumps. We use the Dartmouth isochrones to construct metallicity distribution functions (MDFs) which confirm the presence of dominant populations with = -0.6 to -1.0 dex and considerable metallicity dispersions of 0.2 to 0.3 dex (assuming a 10 Gyr population and scaled-Solar abundances). The average metallicity over the range 30 - 60 kpc is [Fe/H] = -0.8 +/- 0.14 dex, with no evidence for a significant radial gradient. Metal-poor stars ([Fe/H] <= -1.3) typically account for < 10-20 % of the population in each field, irrespective of radius. Assuming our fields are unbiased probes of the dominant stellar populations in these parts, we find that the M31 outer halo remains considerably more metal-rich than that of the Milky Way out to at least 60 kpc.Comment: Accepted for publication in MNRAS. 10 pages, 6 figure

Molecules incorporating a benzothiazole core scaffold inhibit the N-myristoyltransferase of Plasmodium falciparum.

Recombinant N-myristoyltransferase of Plasmodium falciparum (termed PfNMT) has been used in the development of a SPA (scintillation proximity assay) suitable for automation and high-throughput screening of inhibitors against this enzyme. The ability to use the SPA has been facilitated by development of an expression and purification system which yields considerably improved quantities of soluble active recombinant PfNMT compared with previous studies. Specifically, yields of pure protein have been increased from 12 microg x l(-1) to >400 microg x l(-1) by use of a synthetic gene with codon usage optimized for expression in an Escherichia coli host. Preliminary small-scale 'piggyback' inhibitor studies using the SPA have identified a family of related molecules containing a core benzothiazole scaffold with IC50 values 80% at a concentration of 10 microM

The Ital-FLAMES survey of the Sagittarius dwarf Spheroidal galaxy. I. Chemical abundances of bright RGB stars

We present iron and $\alpha$ element (Mg, Ca, Ti) abundances for a sample of 15 Red Giant Branch stars belonging to the main body of the Sagittarius dwarf Spheroidal galaxy. Abundances have been obtained from spectra collected using the high resolution spectrograph FLAMES-UVES mounted at the VLT. Stars of our sample have a mean metallicity of [Fe/H]=-0.41$\pm$0.20 with a metal poor tail extending to [Fe/H]=-1.52. The $\alpha$ element abundance ratios are slightly subsolar for metallicities higher than [Fe/H]\gtsima-1, suggesting a slow star formation rate. The [$\alpha$/Fe] of stars having [Fe/H]$<$-1 are compatible to what observed in Milky Way stars of comparable metallicity.Comment: 16 pages, 10 figures, 6 tables. Accepted for publication in A&A. Minor changes in the tex

The primordial binary population II: Recovering the binary population for intermediate mass stars in Sco OB2

We characterize the binary population in the young and nearby OB association Scorpius OB2 using available observations of visual, spectroscopic, and astrometric binaries with intermediate-mass primaries. We take into account observational biases by comparing the observations with simulated observations of model associations. The available data indicate a large binary fraction (> 70% with 3sigma confidence), with a large probability that all intermediate mass stars in Sco OB2 are part of a binary system. The binary systems have a mass ratio distribution of the form f(q) ~ q^-0.4. Sco OB2 has a semi-major axis distribution of the form f(log a) ~ constant (Opik's law), in the range 5-5e6 Rsun. The log-normal period distribution of Duquennoy & Mayor results in too few spectroscopic binaries, even if the model binary fraction is 100%. Sco OB2 is a young association with a low stellar density; its current population is expected to be very similar to the primordial population. The fact that practically all stars in Sco OB2 are part of a binary (or multiple) system demonstrates that multiplicity is a fundamental factor in the star formation process, at least for intermediate mass stars.Comment: 36 pages, 11 figures, accepted by A&

The Century Survey Galactic Halo Project III: A Complete 4300 deg^2 Survey of Blue Horizontal Branch Stars in the Metal-Weak Thick Disk and Inner Halo

We present a complete spectroscopic survey of 2414 2MASS-selected blue horizontal branch (BHB) candidates selected over 4300 deg^2 of the sky. We identify 655 BHB stars in this non-kinematically selected sample. We calculate the luminosity function of field BHB stars and find evidence for very few hot BHB stars in the field. The BHB stars located at a distance from the Galactic plane |Z|<4 kpc trace what is clearly a metal-weak thick disk population, with a mean metallicity of [Fe/H]= -1.7, a rotation velocity gradient of dv_{rot}/d|Z|= -28+-3.4 km/s in the region |Z|<6 kpc, and a density scale height of h_Z= 1.26+-0.1 kpc. The BHB stars located at 5<|Z|<9 kpc are a predominantly inner-halo population, with a mean metallicity of [Fe/H]= -2.0 and a mean Galactic rotation of -4+-31 km/s. We infer the density of halo and thick disk BHB stars is 104+-37 kpc^-3 near the Sun, and the relative normalization of halo to thick-disk BHB stars is 4+-1% near the Sun.Comment: 12 pages in emulateapj format, accepted for publication in February A