129 research outputs found

    Safe-Guarded Agent Design Pattern for Mechatronic Systems

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    To support the application of real-time Multi-Agent Control Systems (MACS) for mechatronic systems, a combination between the MACS design approach and OROCOS framework has been implemented: the OROCOS-based Implementation Framework for MACS (OROMACS). This paper presents our research results to make the OROMACS framework be easily applicable to develop realtime safe-guarded controller-agents and to maximize the reusability of safe-guarded MACS designs for various types of mechatronic systems. The approach that we advocate is a combination between OROMACS framework and pattern-based design method. Eleven control system design patterns are formed in which the Safe-Guarded Agent, one of the core design patterns, aims at providing a generic and flexible safe-guarded control solution for mechatronic systems. The design patterns are well organized into two reusable generalized safe-guarded control solutions, one for simple mechatronic systems and one for complex mechatronic systems

    Antibiotic usage, dosage and course length in children between 0 and 4 years

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    Antibiotic drugs are most frequently used by 0- to 4-year-old children. We performed a cross-sectional study in the Netherlands using a pharmacy prescription database to investigate the use, dose and course length of antibiotic drugs in 0- to 4-year-olds. We used a database with pharmacy drug-dispensing data. We investigated all prescriptions of systemic antibiotics prescribed in the years 2002-2006 for children of 0-4 years of age. Prescriptions for children under the age of 3 months were excluded. Children of 9-12 months of age received more antibiotics than children in other age groups. In the 3- to 6-month-olds, amoxicillin was prescribed in 75.2% of the cases. This percentage was 50.4% in the 4-year-olds. The contribution of other broad-spectrum antibiotics increased with age (clarithromycin and amoxicillin/clavulanic acid). Small-spectrum penicillins were prescribed less often than the broad-spectrum antibiotics. From the prescriptions of the five most used drugs, 97.6% were within the recommended dose range. Most course lengths corresponded with the guidelines. Of the prescriptions, 3.9% were unlicensed or off-label. Within the group of 0- to 4-year-old children, most antibiotics were used by 9- to 12-month-olds. The doses and course lengths were mostly correct, but the choice of antibiotics was not according to the guidelines. Young children received unlicensed and off-label prescribed antibiotics

    Quasars and their host galaxies

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    This review attempts to describe developments in the fields of quasar and quasar host galaxies in the past five. In this time period, the Sloan and 2dF quasar surveys have added several tens of thousands of quasars, with Sloan quasars being found to z>6. Obscured, or partially obscured quasars have begun to be found in significant numbers. Black hole mass estimates for quasars, and our confidence in them, have improved significantly, allowing a start on relating quasar properties such as radio jet power to fundamental parameters of the quasar such as black hole mass and accretion rate. Quasar host galaxy studies have allowed us to find and characterize the host galaxies of quasars to z>2. Despite these developments, many questions remain unresolved, in particular the origin of the close relationship between black hole mass and galaxy bulge mass/velocity dispersion seen in local galaxies.Comment: Review article, to appear in Astrophysics Update

    Heavy-flavour spectra in high energy nucleus-nucleus collisions

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    The propagation of the heavy quarks produced in relativistic nucleus-nucleus collisions at RHIC and LHC is studied within the framework of Langevin dynamics in the background of an expanding deconfined medium described by ideal and viscous hydrodynamics. The transport coefficients entering into the relativistic Langevin equation are evaluated by matching the hard-thermal-loop result for soft collisions with a perturbative QCD calculation for hard scatterings. The heavy-quark spectra thus obtained are employed to compute the differential cross sections, the nuclear modification factors R_AA and the elliptic flow coefficients v_2 of electrons from heavy-flavour decay.Comment: 22 pages, 20 figures; added one reference, corrected typos and a few figure

    All-particle cosmic ray energy spectrum measured with 26 IceTop stations

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    We report on a measurement of the cosmic ray energy spectrum with the IceTop air shower array, the surface component of the IceCube Neutrino Observatory at the South Pole. The data used in this analysis were taken between June and October, 2007, with 26 surface stations operational at that time, corresponding to about one third of the final array. The fiducial area used in this analysis was 0.122 km^2. The analysis investigated the energy spectrum from 1 to 100 PeV measured for three different zenith angle ranges between 0{\deg} and 46{\deg}. Because of the isotropy of cosmic rays in this energy range the spectra from all zenith angle intervals have to agree. The cosmic-ray energy spectrum was determined under different assumptions on the primary mass composition. Good agreement of spectra in the three zenith angle ranges was found for the assumption of pure proton and a simple two-component model. For zenith angles {\theta} < 30{\deg}, where the mass dependence is smallest, the knee in the cosmic ray energy spectrum was observed between 3.5 and 4.32 PeV, depending on composition assumption. Spectral indices above the knee range from -3.08 to -3.11 depending on primary mass composition assumption. Moreover, an indication of a flattening of the spectrum above 22 PeV were observed.Comment: 38 pages, 17 figure

    An improved method for measuring muon energy using the truncated mean of dE/dx

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    The measurement of muon energy is critical for many analyses in large Cherenkov detectors, particularly those that involve separating extraterrestrial neutrinos from the atmospheric neutrino background. Muon energy has traditionally been determined by measuring the specific energy loss (dE/dx) along the muon's path and relating the dE/dx to the muon energy. Because high-energy muons (E_mu > 1 TeV) lose energy randomly, the spread in dE/dx values is quite large, leading to a typical energy resolution of 0.29 in log10(E_mu) for a muon observed over a 1 km path length in the IceCube detector. In this paper, we present an improved method that uses a truncated mean and other techniques to determine the muon energy. The muon track is divided into separate segments with individual dE/dx values. The elimination of segments with the highest dE/dx results in an overall dE/dx that is more closely correlated to the muon energy. This method results in an energy resolution of 0.22 in log10(E_mu), which gives a 26% improvement. This technique is applicable to any large water or ice detector and potentially to large scintillator or liquid argon detectors.Comment: 12 pages, 16 figure

    Fibrodysplasia ossificans progressiva: what have we achieved and where are we now?: Follow-up to the 2015 Lorentz workshop

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    Fibrodysplasia ossificans progressiva (FOP) is an ultra-rare progressive genetic disease effecting one in a million individuals. During their life, patients with FOP progressively develop bone in the soft tissues resulting in increasing immobility and early death. A mutation in the ACVR1 gene was identified as the causative mutation of FOP in 2006. After this, the pathophysiology of FOP has been further elucidated through the efforts of research groups worldwide. In 2015, a workshop was held to gather these groups and discuss the new challenges in FOP research. Here we present an overview and update on these topics.Diabetes mellitus: pathophysiological changes and therap
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