984 research outputs found

    The Evolution of Spheroidal Galaxies in Different Environments

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    We analyse the kinematic and chemical evolution of 203 distant spheroidal (elliptical and S0) galaxies at 0.2<z<0.8 which are located in different environments (rich clusters, low-mass clusters and in the field). VLT/FORS and CAHA/MOSCA spectra with intermediate-resolution have been acquired to measure the internal kinematics and stellar populations of the galaxies. From HST/ACS and WFPC2 imaging, surface brightness profiles and structural parameters were derived for half of the galaxy sample. The scaling relations of the Faber-Jackson relation and Kormendy relation as well as the Fundamental Plane indicate a moderate evolution for the whole galaxy population in each density regime. In all environments, S0 galaxies show a faster evolution than elliptical galaxies. For the cluster galaxies a slight radial dependence of the evolution out to one virial radius is found. Dividing the samples with respect to their mass, a mass dependent evolution with a stronger evolution of lower-mass galaxies (M<2x10^{11} M_{\sun}) is detected. Evidence for recent star formation is provided by blue colours and weak OII emission or strong H\delta absorption features in the spectra. The results are consistent with a down-sizing formation scenario which is independent from the environment of the galaxies.Comment: 4 pages, 2 figures, to be published in Astronomische Nachrichten (proceedings of Symposium 6 of the JENAM 2008, Vienna

    Cosmology and Cluster Halo Scaling Relations

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    We explore the effects of dark matter and dark energy on the dynamical scaling properties of galaxy clusters. We investigate the cluster Faber-Jackson (FJ), Kormendy and Fundamental Plane (FP) relations between the mass, radius and velocity dispersion of cluster size halos in cosmological NN-body simulations. The simulations span a wide range of cosmological parameters, representing open, flat and closed Universes. Independently of the cosmology, we find that the simulated clusters are close to a perfect virial state and do indeed define a Fundamental Plane. The fitted parameters of the FJ, Kormendy and FP relationships do not show any significant dependence on Ωm\Omega_m and/or ΩΛ\Omega_{\Lambda}. The one outstanding effect is the influence of Ωm\Omega_{m} on the thickness of the Fundamental Plane. Following the time evolution of our models, we find slight changes of FJ and Kormendy parameters in high Ωm\Omega_m universe, along with a slight decrease of FP fitting parameters. We also see an initial increase of the FP thickness followed by a convergence to a nearly constant value. The epoch of convergence is later for higher values of Ωm\Omega_m while the thickness remains constant in the low Ωm\Omega_m Λ\Lambda-models. We also find a continuous increase of the FP thickness in the Standard CDM (SCDM) cosmology. There is no evidence that these differences are due to the different power spectrum slope at cluster scales. From the point of view of the FP, there is little difference between clusters that quietly accreted their mass and those that underwent massive mergers. The principal effect of strong mergers is to change significantly the ratio of the half-mass radius rhalfr_{half} to the harmonic mean radius rhr_h.Comment: 24 pages, 17 figures, submitted to MNRA

    Large‐scale calculations of excitation energies in coupled cluster theory : The singlet excited states of benzene

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    Algorithms for calculating singlet excitation energies in the coupled cluster singles and doubles (CCSD) model are discussed and an implementation of an atomic‐integral direct algorithm is presented. Each excitation energy is calculated at a cost comparable to that of the CCSD ground‐state energy. Singlet excitation energies are calculated for benzene using up to 432 basis functions. Basis‐set effects of the order of 0.2 eV are observed when the basis is increased from augmented polarized valence double‐zeta (aug‐cc‐pVDZ) to augmented polarized valence triple‐zeta (aug‐cc‐pVTZ) quality. The correlation problem is examined by performing calculations in the hierarchy of coupled cluster models CCS, CC2, CCSD, and CC3, as well as by using the CCSDR(3) perturbative triples corrections. The effect of triple excitations are less than 0.2 eV for all excitations except for the 2 1E2g state. The calculated excitation energies are compared with experiment and other theoretical [email protected]

    High-precision photometry by telescope defocussing - VI. WASP-24, WASP-25 and WASP-26

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    The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013/) under grant agreement nos. 229517 and 268421. This publication was supported by grants NPRP 09-476-1-078 and NPRP X-019-1-006 from Qatar National Research Fund (a member of Qatar Foundation). TCH acknowledges financial support from the Korea Research Council for Fundamental Science and Technology (KRCF) through the Young Research Scientist Fellowship Programme and is supported by the KASI (Korea Astronomy and Space Science Institute) grant 2012-1-410-02/2013-9-400-00. SG, XW and XF acknowledge the support from NSFC under the grant no. 10873031. The research is supported by the ASTERISK project (ASTERoseismic Investigations with SONG and Kepler) funded by the European Research Council (grant agreement no. 267864). DR, YD, AE, FF (ARC), OW (FNRS research fellow) and J Surdej acknowledge support from the Communauté française de Belgique – Actions de recherche concertées – Académie Wallonie-Europe.We present time series photometric observations of 13 transits in the planetary systems WASP-24, WASP-25 and WASP-26. All three systems have orbital obliquity measurements, WASP-24 and WASP-26 have been observed with Spitzer, and WASP-25 was previously comparatively neglected. Our light curves were obtained using the telescope-defocussing method and have scatters of 0.5–1.2 mmag relative to their best-fitting geometric models. We use these data to measure the physical properties and orbital ephemerides of the systems to high precision, finding that our improved measurements are in good agreement with previous studies. High-resolution Lucky Imaging observations of all three targets show no evidence for faint stars close enough to contaminate our photometry. We confirm the eclipsing nature of the star closest to WASP-24 and present the detection of a detached eclipsing binary within 4.25 arcmin of WASP-26.Publisher PDFPeer reviewe

    Impact of rs361072 in the Phosphoinositide 3-Kinase p110β Gene on Whole-Body Glucose Metabolism and Subunit Protein Expression in Skeletal Muscle

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    OBJECTIVE-Phosphoinositide 3-kinase (PI3K) is a major effector in insulin signaling. rs361072, located in the promoter of the gene (PIK3CB) for the p110 beta subunit, has previously been found to be associated with homeostasis model assessment for insulin resistance (HOMA-IR) in obese subjects. The aim was to investigate the influence of rs361072 on in vivo glucose metabolism, skeletal muscle PI3K subunit protein levels, and type 2 diabetes. RESEARCH DESIGN AND METHODS-The functional role of rs361072 was studied in 196 Danish healthy adult twins. Peripheral and hepatic insulin sensitivity was assessed by a euglycemic-hyperinsulinemic clamp. Basal and insulin-stimulated biopsies were taken from the vastus lateralis muscle, and tissue p110 beta and p85 alpha proteins were measured by Western blotting. The genetic association with type 2 diabetes and quantitative metabolic traits was investigated in 9,316 Danes with glucose tolerance ranging from normal to overt type 2 diabetes. RESULTS-While hepatic insulin resistance was similar in the fasting state, carriers of the minor G allele had lower hepatic glucose output (per-allele effect: 16%, P-add = 0.004) during high physiological insulin infusion. rs361072 did not associate with insulin-stimulated peripheral glucose disposal despite a decreased muscle p85 alpha:p110 beta protein ratio (P-add = 0.03) in G allele carriers. No association with HOMA-IR or type 2 diabetes (odds ratio 1.07, P = 0.5) was identified, and obesity did not interact with rs361072 on these traits. CONCLUSIONS-Our study suggests that the minor G allele of PIK3CB rs361072 associates with decreased muscle p85 alpha:p110 beta ratio and lower hepatic glucose production at high plasma insulin levels. However, no impact on type 2 diabetes prevalence was found. Diabetes 59:1108-1112, 201

    <i>Spitzer</i> microlens measurement of a massive remnant in a well-separated binary

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    We report the detection and mass measurement of a binary lens OGLE-2015-BLG-1285La,b, with the more massive component having M1 > 1.35 M⊙ (80% probability). A main-sequence star in this mass range is ruled out by limits on blue light, meaning that a primary in this mass range must be a neutron star (NS) or black hole (BH). The system has a projected separation r⊥ = 6.1 ± 0.4 AU and lies in the Galactic bulge. These measurements are based on the "microlens parallax" effect, i.e., comparing the microlensing light curve as seen from Spitzer, which lay at 1.25 AU projected from Earth, to the light curves from four ground-based surveys, three in the optical and one in the near-infrared. Future adaptive optics imaging of the companion by 30 m class telescopes will yield a much more accurate measurement of the primary mass. This discovery both opens the path and defines the challenges to detecting and characterizing BHs and NSs in wide binaries, with either dark or luminous companions. In particular, we discuss lessons that can be applied to future Spitzer and Kepler K2 microlensing parallax observations

    Renewable estimation and incremental inference in generalized linear models with streaming data sets

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153655/1/rssb12352_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153655/2/rssb12352-sup-0001-Supinfo.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153655/3/rssb12352.pd

    Variants Near MC4R Are Associated With Obesity and Influence Obesity-Related Quantitative Traits in a Population of Middle-Aged People: Studies of 14,940 Danes

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    OBJECTIVE— Variants downstream of the melanocortin-4 receptor gene (MC4R) have been reported to associate with obesity. We examined rs17782313, rs17700633, rs12970134, rs477181, rs502933, and rs4450508 near MC4R for association with obesity-related quantitative traits, obesity, and type 2 diabetes in Danish individuals

    Comparing nuclear power trajectories in Germany and the UK: from ‘regimes' to ‘democracies’ in sociotechnical transitions and Discontinuities

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    This paper focuses on arguably the single most striking contrast in contemporary major energy politics in Europe (and even the developed world as a whole): the starkly differing civil nuclear policies of Germany and the UK. Germany is seeking entirely to phase out nuclear power by 2022. Yet the UK advocates a ‘nuclear renaissance’, promoting the most ambitious new nuclear construction programme in Western Europe.Here,this paper poses a simple yet quite fundamental question: what are the particular divergent conditions most strongly implicated in the contrasting developments in these two countries. With nuclear playing such an iconic role in historical discussions over technological continuity and transformation, answering this may assist in wider understandings of sociotechnical incumbency and discontinuity in the burgeoning field of‘sustainability transitions’. To this end, an ‘abductive’ approach is taken: deploying nine potentially relevant criteria for understanding the different directions pursued in Germany and the UK. Together constituted by 30 parameters spanning literatures related to socio-technical regimes in general as well as nuclear technology in particular, the criteria are divided into those that are ‘internal’ and ‘external’ to the ‘focal regime configuration’ of nuclear power and associated ‘challenger technologies’ like renewables. It is ‘internal’ criteria that are emphasised in conventional sociotechnical regime theory, with ‘external’ criteria relatively less well explored. Asking under each criterion whether attempted discontinuation of nuclear power would be more likely in Germany or the UK, a clear picture emerges. ‘Internal’ criteria suggest attempted nuclear discontinuation should be more likely in the UK than in Germany– the reverse of what is occurring. ‘External’ criteria are more aligned with observed dynamics –especially those relating to military nuclear commitments and broader ‘qualities of democracy’. Despite many differences of framing concerning exactly what constitutes ‘democracy’, a rich political science literature on this point is unanimous in characterising Germany more positively than the UK. Although based only on a single case,a potentially important question is nonetheless raised as to whether sociotechnical regime theory might usefully give greater attention to the general importance of various aspects of democracy in constituting conditions for significant technological discontinuities and transformations. If so, the policy implications are significant. A number of important areas are identified for future research, including the roles of diverse understandings and specific aspects of democracy and the particular relevance of military nuclear commitments– whose under-discussion in civil nuclear policy literatures raises its own questions of democratic accountability
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