786 research outputs found

    Ultrasound exploration in the work-up of unexplained fever in the immunocompromized host: preliminary observations.

    Get PDF
    In immunocompromized hosts, febrile episodes have an unknown origin (FUO) in about fifty per cent of cases. In this preliminary study we evaluated the role of abdominal and pleural ultrasound (US) examination for early detection of infectious sites. US exploration was performed in a cohort of 14 consecutive FUO patients early after fever onset, at patients’ bedside, by a hematologist trained in diagnostic ultrasound, and it was repeated at neutrophil recovery. US exploration showed abnormal abdominal findings in 7 and pleural effusion in 3 patients. In all cases but one the abnormality was found at the first US examination. Abdominal and pleural US exploration is a low-cost, easy to use tool for the work-up of FUO in the immunocompromized host that proved to be effective in identifying the infection site in about 50% of patients

    Size-dependent recombination dynamics in ZnO nanowires

    Get PDF
    This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett. 96, 053105 (2010) and may be found at https://doi.org/10.1063/1.3294327.A deep understanding of the recombination dynamics of ZnO nanowires (NWs) is a natural step for a precise design of on-demand nanostructures based on this material system. In this work we investigate the influence of finite-size on the recombination dynamics of the neutral bound exciton around 3.365 eV for ZnO NWs with different diameters. We demonstrate that the lifetime of this excitonic transition decreases with increasing the surface-to-volume ratio due to a surface induced recombination process. Furthermore, we have observed two broad transitions around 3.341 and 3.314 eV, which were identified as surface states by studying the dependence of their life time and intensitiy with the NWs dimensions.DFG, 43659573, SFB 787: Halbleiter - Nanophotonik: Materialien, Modelle, Bauelement

    Recombination dynamics in ZnO nanowires: Surfaces states versus mode quality factor

    Get PDF
    This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett. 97, 133116 (2010) and may be found at https://doi.org/10.1063/1.3496444.In this work, we investigate the influence of finite size on the recombinations dynamics of ZnO nanowires. We demonstrate that diameter as well as length of nanowires determine the lifetime of the neutral donor bound excitons. Our findings suggest that while the length is mainly responsible for different mode quality factors of the cavity-like nanowires, the diameter determines the influence of surface states as alternative recombinations channels for the optical modes trapped in the nanocavity. In addition, comparing nanowires grown using different catalyst we show that the surfaces states strongly depend on each precursor characteristics.DFG, 43659573, SFB 787: Halbleiter - Nanophotonik: Materialien, Modelle, BauelementeDFG, 53182490, EXC 314: Unifying Concepts in Catalysi

    Regulatory Dynamics on Random Networks: Asymptotic Periodicity and Modularity

    Full text link
    We study the dynamics of discrete-time regulatory networks on random digraphs. For this we define ensembles of deterministic orbits of random regulatory networks, and introduce some statistical indicators related to the long-term dynamics of the system. We prove that, in a random regulatory network, initial conditions converge almost surely to a periodic attractor. We study the subnetworks, which we call modules, where the periodic asymptotic oscillations are concentrated. We proof that those modules are dynamically equivalent to independent regulatory networks.Comment: 23 pages, 3 figure

    Scoring and Classifying Implicit Positive Interpretations:A Challenge of Class Imbalance

    Get PDF
    This paper reports on a reimplementation of a system on detecting implicit positive meaning from negated statements. In the original regression experiment, different positive interpretations per negation are scored according to their likelihood. We convert the scores to classes and report our results on both the regression and classification tasks. We show that a baseline taking the mean score or most frequent class is hard to beat because of class imbalance in the dataset. Our error analysis indicates that an approach that takes the information structure into account (i.e. which information is new or contrastive) may be promising, which requires looking beyond the syntactic and semantic characteristics of negated statements

    The early modern Dutch mediascape. Detecting media mentions in chronicles using word embeddings and CRF

    Get PDF
    Collective identities and transnational networks in medieval and early modern Europe, 1000-180

    High-power nitrided TiO2 carbon felt as the negative electrode for all-vanadium redox flow batteries

    Get PDF
    This work describes the design of an electrode with enhanced performance applied to all-vanadium redox flow batteries (VRFBs). This new electrode consists of a structural porous carbon felt decorated with TiO2 rutile nanoparticles, which has been nitrided using ammonolysis at 900 °C. An outstanding charge and mass transfer over the electrode-electrolyte interface was observed as a consequence of the synergetic effect of N- and O-functionalization over carbon felt (CF) and the partial formation of TiN (metallic conductor) phase. Moreover, this material has not only improved in terms of catalysis towards the V3+/V2+ redox reaction (k0 = 1.6 × 10−3 cm s−1), but also inhibited the hydrogen evolution reaction (HER), which is one of the main causes of imbalances that lead to battery failure. This led to an impressive high-power peak output value up to 700 mW cm−2, as well as work at high current density in galvanostatic conditions (i.e. 150 mA cm−2), exhibiting low ohmic losses (overpotential) and great redox single cell reversibility, with a superior energy efficiency of 71%. An inexpensive, earth abundant and scalable synthesis method to boost VRFBs technology based on nitrided CF@TiO2 is presented, being able to overcome certain constrains, and therefore to achieve high energy and power densities
    • …
    corecore