10,090 research outputs found

    New distinguished classes of spectral spaces: a survey

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    In the present survey paper, we present several new classes of Hochster's spectral spaces "occurring in nature", actually in multiplicative ideal theory, and not linked to or realized in an explicit way by prime spectra of rings. The general setting is the space of the semistar operations (of finite type), endowed with a Zariski-like topology, which turns out to be a natural topological extension of the space of the overrings of an integral domain, endowed with a topology introduced by Zariski. One of the key tool is a recent characterization of spectral spaces, based on the ultrafilter topology, given in a paper by C. Finocchiaro in Comm. Algebra 2014. Several applications are also discussed

    Phonon Properties of Knbo3 and Ktao3 from First-Principles Calculations

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    The frequencies of transverse-optical Γ\Gamma phonons in KNbO3_3 and KTaO3_3 are calculated in the frozen-phonon scheme making use of the full-potential linearized muffin-tin orbital method. The calculated frequencies in the cubic phase of KNbO3_3 and in the tetragonal ferroelectric phase are in good agreement with experimental data. For KTaO3_3, the effect of lattice volume was found to be substantial on the frequency of the soft mode, but rather small on the relative displacement patterns of atoms in all three modes of the T1uT_{1u} symmetry. The TO frequencies in KTaO3_3 are found to be of the order of, but somehow higher than, the corresponding frequencies in cubic KNbO3_3.Comment: 8 pages + 1 LaTeX figure, Revtex 3.0, SISSA-CM-94-00

    A review of the criteria for non-invasive diagnosis of cardiac transthyretin amyloidosis

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    Introduction: Cardiac transthyretin (ATTR) amyloidosis is a progressive and fatal infiltrative cardiomyopathy (ATTR-CM) characterized by congestive cardiac failure, often with preserved left ventricular ejection fraction, and significant risk of conduction disease. Diagnosis is often delayed or missed due to poor specificity of echocardiography and the historical requirement for a histological diagnosis, frequently an endomyocardial biopsy. Areas covered: Following a detailed literature review focusing on peer reviewed articles (Pubmed, Cochrane Library, Google Scholar), from 1995 to 2020, alongside international diagnostic guidelines and expert opinion in the field, this article will explore the current non-invasive diagnostic criteria for ATTR-CM including the role of transthoracic echocardiography, cardiac MRI, bone scintigraphy, and assessment for exclusion of a clonal dyscrasia. Expert opinion: ATTR-CM is an emerging and increasingly diagnosed cause of heart failure, particularly in the elderly. Promising novel therapies make accurate and swift diagnosis of the disease vital. With the increasing use of cardiac MRI to investigate cardiomyopathy and repurposing of technetium-labeledbone scintigraphy, clinicians are now often able to diagnose ATTR-CM without recourse to an endomyocardial biopsy

    Ground‐State Wavefunctions and Energies for the Helium Isoelectronic Series through Z = 10

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69577/2/JCPSA6-47-8-3077-1.pd

    Configuration Interaction in Two‐ and Three‐Electron Atoms

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    The ground states of the first four members of the helium isoelectronic series and the 22S and 22P states of lithium are calculated using a configuration‐interaction expansion in a complete denumerable set of single‐particle functions, with one adjustable scale parameter. The best energies for the two‐electron systems, obtained with 120‐term expansions, are E(H−) = −0.52748, E(He) = −2.90335, E(Li+) = −7.27945, and E(Be+ +) = −13.65504, in units of e2/a0. The energies for all but He are lower than any heretofore obtained with a configuration‐interaction approach. The dependence of energy on scale factor is found to be very pronounced, in contrast to the corresponding behavior for wavefunctions which contain the interparticle coordinates explicitly. The best energies for the lithium states, obtained with 208‐term expansions, are E(22S) = −7.47369 and E(22P) = −7.40366. The 22S energy is not as good as has been obtained with either expansions in terms of interparticle coordinates or configuration interaction with many nonlinear parameters. The 22P energy is of approximately the same accuracy but is lower than any previously published.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70610/2/JCPSA6-45-11-4248-1.pd

    Galaxy Counts, Sizes, Colours and Redshifts in the Hubble Deep Field

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    We compare the galaxy evolution models of Bruzual & Charlot (1993) with the faint galaxy count, size and colour data from the Hubble and Herschel Deep Fields (Metcalfe et al 1996). For qo=0.05, we find that models where the SFR increases exponentially out to z>2 are consistent with all of the observational data. For qo=0.5, such models require an extra population of galaxies which are only seen at high redshift and then rapidly fade or disappear. We find that, whatever the cosmology, the redshift of the faint blue galaxies and hence the epoch of galaxy formation is likely to lie at z>2. We find no implied peak in the SFR at z=1 and we suggest that the reasons for this contradiction with the results of Madau et al (1996) include differences in faint galaxy photometry, in the treatment of spiral dust and in the local galaxy count normalisation.Comment: 8 pages, 5 eps figures, needs paspconf.st

    The evolution of the AGN content in groups up to z~1

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    Determining the AGN content in structures of different mass/velocity dispersion and comparing them to higher mass/lower redshift analogs is important to understand how the AGN formation process is related to environmental properties. We use our well-tested cluster finding algorithm to identify structures in the GOODS North and South fields, exploiting the available spectroscopic redshifts and accurate photometric redshifts. We identify 9 structures in GOODS-south (presented in a previous paper) and 8 new structures in GOODS-north. We only consider structures where at least 2/3 of the members brighter than M_R=-20 have a spectroscopic redshift. For those group members that coincide with X-ray sources in the 4 and 2 Msec Chandra source catalogs respectively, we determine if the X-ray emission originates from AGN activity or it is related to the galaxies' star-formation activity. We find that the fraction of AGN with Log L_H > 42 erg/s in galaxies with M_R < -20 is on average 6.3+-1.3%, much higher than in lower redshift groups of similar mass and more than double the fraction found in massive clusters at a similarly high redshift. We then explore the spatial distribution of AGN in the structures and find that they preferentially populate the outer regions. The colors of AGN host galaxies in structures tend to be confined to the green valley, thus avoiding the blue cloud and, partially, also the red-sequence, contrary to what happens in the field. We finally compare our results to the predictions of two sets of semi analytic models to investigate the evolution of AGN and evaluate potential triggering and fueling mechanisms. The outcome of this comparison attests the importance of galaxy encounters, not necessarily leading to mergers, as an efficient AGN triggering mechanism. (abridged)Comment: 11 pages, 8 figures, Accepted accepted for publication in A&

    Evidence of anomalous dispersion of the generalized sound velocity in glasses

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    The dynamic structure factor, S(Q,w), of vitreous silica, has been measured by inelastic X-ray scattering in the exchanged wavevector (Q) region Q=4-16.5 nm-1 and up to energies hw=115 meV in the Stokes side. The unprecedented statistical accuracy in such an extended energy range allows to accurately determine the longitudinal current spectra, and the energies of the vibrational excitations. The simultaneous observation of two excitations in the acoustic region, and the persistence of propagating sound waves up to Q values comparable with the (pseudo-)Brillouin zone edge, allow to observe a positive dispersion in the generalized sound velocity that, around Q=5 nm-1, varies from 6500 to 9000 m/s: this phenomenon was never experimentally observed in a glass.Comment: 5 pages, 3 figures. To appear in Phys. Rev.

    T-PHOT version 2.0: improved algorithms for background subtraction, local convolution, kernel registration, and new options

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    We present the new release v2.0 of T-PHOT, a publicly available software package developed to perform PSF-matched, prior-based, multiwavelength deconfusion photometry of extragalactic fields. New features included in the code are presented and discussed: background estimation, fitting using position dependent kernels, flux prioring, diagnostical statistics on the residual image, exclusion of selected sources from the model and residual images, individual registration of fitted objects. These new options improve on the performance of the code, allowing for more accurate results and providing useful aids for diagnostics.Comment: 7 pages, 8 figure

    First Results from the KMOS Lens-Amplified Spectroscopic Survey (KLASS): Kinematics of Lensed Galaxies at Cosmic Noon

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    We present the first results of the KMOS Lens-Amplified Spectroscopic Survey (KLASS), a new ESO Very Large Telescope (VLT) large program, doing multi-object integral field spectroscopy of galaxies gravitationally lensed behind seven galaxy clusters selected from the HST Grism Lens-Amplified Survey from Space (GLASS). Using the power of the cluster magnification we are able to reveal the kinematic structure of 25 galaxies at 0.7z2.30.7 \lesssim z \lesssim 2.3, in four cluster fields, with stellar masses 8log(M/M)118 \lesssim \log{(M_\star/M_\odot)} \lesssim 11. This sample includes 5 sources at z>1z>1 with lower stellar masses than in any previous kinematic IFU surveys. Our sample displays a diversity in kinematic structure over this mass and redshift range. The majority of our kinematically resolved sample is rotationally supported, but with a lower ratio of rotational velocity to velocity dispersion than in the local universe, indicating the fraction of dynamically hot disks changes with cosmic time. We find no galaxies with stellar mass <3×109M<3 \times 10^9 M_\odot in our sample display regular ordered rotation. Using the enhanced spatial resolution from lensing, we resolve a lower number of dispersion dominated systems compared to field surveys, competitive with findings from surveys using adaptive optics. We find that the KMOS IFUs recover emission line flux from HST grism-selected objects more faithfully than slit spectrographs. With artificial slits we estimate slit spectrographs miss on average 60% of the total flux of emission lines, which decreases rapidly if the emission line is spatially offset from the continuum.Comment: Accepted for publication in Ap
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