24,057 research outputs found

    Modelling galaxy stellar mass evolution from z~0.8 to today

    Get PDF
    We apply the empirical method built for z=0 in the previous work of Wang et al. to a higher redshift, to link galaxy stellar mass directly with its hosting dark matter halo mass at z~0.8. The relation of the galaxy stellar mass and the host halo mass M_infall is constrained by fitting both the stellar mass function and the correlation functions at different stellar mass intervals of the VVDS observation, where M_infall is the mass of the hosting halo at the time when the galaxy was last the central galaxy. We find that for low mass haloes, their residing central galaxies are less massive at high redshift than those at low redshift. For high mass haloes, central galaxies in these haloes at high redshift are a bit more massive than the galaxies at low redshift. Satellite galaxies are less massive at earlier times, for any given mass of hosting haloes. Fitting both the SDSS and VVDS observations simultaneously, we also propose a unified model of the M_stars-M_infall relation, which describes the evolution of central galaxy mass as a function of time. The stellar mass of a satellite galaxy is determined by the same M_stars-M_infall relation of central galaxies at the time when the galaxy is accreted. With these models, we study the amount of galaxy stellar mass increased from z~0.8 to the present day through galaxy mergers and star formation. Low mass galaxies gain their stellar masses from z~0.8 to z=0 mainly through star formation. For galaxies of higher mass, the increase of stellar mass solely through mergers from z=0.8 can make the massive galaxies a factor ~2 larger than observed at z=0. We can also predict stellar mass functions of redshifts up to z~3, and the results are consistent with the latest observations.Comment: 12 pages, 10 figures, accepted for publication in MNRA

    Superconformal indices of three-dimensional theories related by mirror symmetry

    Full text link
    Recently, Kim and Imamura and Yokoyama derived an exact formula for superconformal indices in three-dimensional field theories. Using their results, we prove analytically the equality of superconformal indices in some U(1)-gauge group theories related by the mirror symmetry. The proofs are based on the well known identities of the theory of qq-special functions. We also suggest the general index formula taking into account the U(1)JU(1)_J global symmetry present for abelian theories.Comment: 17 pages; minor change

    Total hepatectomy and liver transplant for hepatocellular adenomatosis and focal nodular hyperplasia.

    Get PDF
    Extensive hepatocellular adenomatosis (HA) and focal nodular hyperplasia (FNH) represent a proliferation of hepatic cells that occurs most frequently in women. These lesions are uncommon in the pediatric age group, accounting for 2% of pediatric hepatic tumors, and are extremely rare in males. The etiology of HA and FNH has been correlated with the use of oral contraceptives. We report to the best of our knowledge the first series of patients treated with OLTx for HA and FNH (five cases). All these patients had lesions involving at least 90% of the hepatic parenchyma and all underwent major hepatic surgery before OLTx because of life threatening complications. One patient died in the immediate postoperative period following retransplantation for primary non-function of the first OLTx. Four out of five patients are currently alive from 4.1 to 9.6 years after OLTx. Our results justify the use of OLTx for symptomatic patients with HA and FNH who cannot be treated with conventional hepatic resections

    Large-scale network organization in the avian forebrain: a connectivity matrix and theoretical analysis

    Get PDF
    Many species of birds, including pigeons, possess demonstrable cognitive capacities, and some are capable of cognitive feats matching those of apes. Since mammalian cortex is laminar while the avian telencephalon is nucleated, it is natural to ask whether the brains of these two cognitively capable taxa, despite their apparent anatomical dissimilarities, might exhibit common principles of organisation on some level. Complementing recent investigations of macro-scale brain connectivity in mammals, including humans and macaques, we here present the first large-scale wiring diagram for the forebrain of a bird. Using graph theory, we show that the pigeon telencephalon is organised along similar lines to that of a mammal. Both are modular, small-world networks with a connective core of hub nodes that includes prefrontal-like and hippocampal structures. These hub nodes are, topologically speaking, the most central regions of the pigeon's brain, as well as being the most richly connected, implying a crucial role in information flow. Overall, our analysis suggests that indeed, despite the absence of cortical layers and close to 300 million years of separate evolution, the connectivity of the avian brain conforms to the same organisational principles as the mammalian brain

    On the Impact of Link Layer Retransmissions on TCP for Aeronautical Communications

    Get PDF
    In this article, we evaluate the impact of link layer retransmissions on the performance of TCP in the context of aeronautical communications.We present the architecture of aeronautical networks, which is manly driven by an important channel access delay, and the various retransmission strategies that can be implemented at both link and transport layers. We consider a worst case scenario to illustrate the benefits provided by the ARQ scheme at the link layer in terms of transmission delay.We evaluate the trade-off between allowing a fast data transmission and a low usage of satellite capacity by adjusting link layer parameters

    Association of Sporadic Moderate-Vigorous Physical Activity with Cardiovascular Disease Risk Factors - A Systematic Review

    Get PDF
    Background: Physical activity is an important factor controlling chronic diseases such as ....

    Hyperbolic metamaterials for terahertz applications

    Get PDF
    We develop a method for fabricating hyperbolic metamaterials for terahertz (THz) applications. We prepare a porous silicon matrix with a triangular lattice of holes, which we fill with copper by means of electrochemical deposition. We study transmission properties of this wire medium using THz time-domain spectroscopy, and demonstrate hyperbolic media properties
    corecore