25 research outputs found

    Radio source feedback in galaxy evolution

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    We present a galaxy evolution model which incorporates a physically motivated implementation of AGN feedback. Intermittent jets inflate cocoons of radio plasma which then expand supersonically, shock heating the ambient gas. The model reproduces observed star formation histories to the highest redshifts for which reliable data exists, as well as the observed galaxy colour bimodality. Intermittent radio source feedback also naturally provides a way of keeping the black hole and spheroid growth in step. We find possible evidence for a top-heavy Initial Mass Function (IMF) for z>2z>2, consistent with observations of element abundances, and sub-mm and Lyman break galaxy counts.Comment: 37 pages, 14 figures, ApJ (in press

    Characterization of Geographical and Meteorological Parameters

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    [EN]This chapter is devoted to the introduction of some geographical and meteorological information involved in the numerical modeling of wind fields and solar radiation. First, a brief description of the topographical data given by a Digital Elevation Model and Land Cover databases is provided. In particular, the Information System of Land Cover of Spain (SIOSE) is considered. The study is focused on the roughness length and the displacement height parameters that appear in the logarithmic wind profile, as well as in the albedo related to solar radiation computation. An extended literature review and characterization of both parameters are reported. Next, the concept of atmospheric stability is introduced from the Monin–Obukhov similarity theory to the recent revision of Zilitinkevich of the Neutral and Stable Boundary Layers (SBL). The latter considers the effect of the free-flow static stability and baroclinicity on the turbulent transport of momentum and of the Convective Boundary Layers (CBL), more precisely, the scalars in the boundary layer, as well as the model of turbulent entrainment

    Alloplastische Implantate in der Kopf- und Halschirurgie.

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    An Asynchronous Message Passing and Concurrent Scheme Implementation

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    This thesis investigates the power of a Scheme implementation extended with processes using an asynchronous message passing style very much in common with the functional programming language Erlang. Patterns and pattern matching have been added to the language in order to support out of order message selection. Each process is equipped with a local heap to store its local data and a single global heap contains the shared data of all processes reducing the potential bottleneck of local garbage collection. We will show by examples that this implementation of Scheme improves the expressiveness of the language compared to Erlang and that lambda abstractions and continuations are fruitful elements for concurrent programming. In particular we will show how to make representation independent data protocols and how to migrate recursive computations. Contents 1 Introduction 4 1.1 Scheme -- an Appropriate Choice . . . . . . . . . . . . . . . . . . 4 2 The Language 6 2.1 Patterns . . . . . ...

    Does the meld system provide equal access to liver transplantation for patients with different ABO blood groups?

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    This study investigates the relationship between blood group and waiting time until transplantation or death on the waiting list. All patients listed for liver transplantation in the Netherlands between 15 December 2006 and 31 December 2012, were included. Study variables were gender, age, year of listing, diagnosis, previous transplantations, blood group, urgency, and MELD score. Using a competing risks analysis, separate cumulative incidence curves were constructed for death on the waiting list and transplantation and used to evaluate outcomes.In 517 listings, the mean death rate per 100 patient-years was 10.4. A total of 375 (72.5% of all listings) were transplanted. Of all transplantations, 352 (93.9%) were ABO-identical and 23 (6.1%) ABO-compatible. The 5-year cumulative incidence of death was 11.2% (SE 1.4%), and of transplantation 72.5% (SE 2.0%). Patient blood group had no multivariate significant impact on the hazard of dying on the waiting list nor on transplantation. Age, MELD score, and urgency status were significantly related to the death on the waiting list and transplantation. More recent listing had higher probability of being transplanted. In the MELD era, patient blood group status does not have a significant impact on liver transplant waiting list mortality nor on waiting time for transplantation

    The price of donation after cardiac death in liver transplantation:a prospective cost-effectiveness study

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    <p>This study aims to perform a detailed prospective observational multicenter cost-effectiveness study by comparing liver transplantations with Donation after Brain Death (DBD) and Donation after Cardiac Death (DCD) grafts. All liver transplantations in the three Dutch liver transplant centers between 2004 and 2009 were included with 1-year follow-up. Primary outcome parameter was cost per life year after transplantation. Secondary outcome parameters were 1-year patient and graft survival, complications, and patient-level costs. From 382 recipients that underwent 423 liver transplantations, 293 were primarily transplanted with DBD and 89 with DCD organs. Baseline characteristics were not different between both groups. The Donor Risk Index was significantly different as were cold and warm ischemic time. Ward stay was significantly longer in DCD transplantations. Patient and graft survival were not significantly different. Patients receiving DCD organs had more and more severe complications. The cost per life year for DBD was Euro 88 913 compared to Euro 112 376 for DCD. This difference was statistically significant. DCD livers have more and more severe complications, more reinterventions and consequently higher costs than DBD livers. However, patient and graft survival was not different in this study. Reimbursement should be differentiated to better accommodate DCD transplantations.</p>
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