54 research outputs found

    Ionoacoustics for three-dimensional particle bunch monitoring

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    Ionoacoustics refers to the measurement of acoustic waves excited by ions as they slow down in matter. One particularly interesting application is the monitoring of individual laser-accelerated ion bunches, which challenges many established online detection systems. The ionoacoustic approach offers advantages in this context. It is resistant to the strong electromagnetic pulse emitted during the laser-plasma interaction, and it does not exhibit saturation even at very high particle fluxes. Recovering the Ion-Bunch Energy distribution from a recorded Acoustic Trace (I-BEAT) has conceptually been proven. This work introduces two new detector designs, the I-BEAT 3D and the TI-BEAT detector, and develops a fast analysis routine based on an analytical model. The result is a novel and versatile online detector for short and intense ion bunches that enables immediate feedback. Describing the dose deposition of protons in matter, particularly in the entrance window and the water reservoir of the detector, connects the most important proton bunch parameters to the resulting ionoacoustic signals and hence serves for the development of a simple and fast data analysis method for particle bunches with Gaussian energy spectra and lateral distributions. This is key to the analysis and interpretation of the acoustic traces obtained with the detector designs. The I-BEAT 3D detector uses four transducers and is studied in experiments at two laser-driven proton beamlines located at CALA and the HZDR. Via the new analytical model, it provides the mean bunch energy, energy spread and lateral bunch position of individual bunches in less than one second. Additionally, the detector allows the monitoring of relative changes in lateral bunch size. Experiments with proton bunches at kinetic energies between 10 MeV and 30 MeV reveal sub-MeV and sub-mm resolution. Cross-calibration using radiochromic films proves that the new methodology can determine the absolute number of particles contained in a single bunch with uncertainties of only 10%. The TI-BEAT detector uses a short water reservoir to allow ions with sufficient energy to pass through. It is developed to prove that ionoacoustics can also function as transmission monitor for particle bunches. The detector concept is evaluated at the GSI’s SIS-18 synchrotron with xenon ions at kinetic energies of 385 MeV/u. The precision of determining the absolute lateral position and relative changes in the lateral size of ion bunches is 0.15 mm and less than 0.1 mm, respectively. The particle number is extracted with a precision between 4% and 8%. The new detector designs and the data evaluation method provide a fast, compact, cost-effective and electromagnetic pulse-resistant online tool for monitoring important ion bunch parameters at application sites. This provides the foundation for irradiation studies and can serve as feedback for automated optimization of laser-driven proton sources

    Emergence of novel ST1299 vanA lineages as possible cause for the striking rise of vancomycin resistance among invasive strains of Enterococcus faecium at a German university hospital

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    ABSTRACT Since 2019, we have observed a remarkable rise of vancomycin resistance among invasive strains of Enterococcus (E.) faecium at the University Hospital Erlangen (UKER), a tertiary-care hospital in Germany. Here, we analyzed the genetic diversity of E. faecium isolated from blood cultures of in-patients by core genome multilocus sequence typing to see whether the occurrence of vancomycin resistance was associated with the spread of new clonal lineages. Between January and December 2022, 37 consecutive non-duplicate isolates were included in this study. Resistance to vancomycin was detected in 15 isolates (40.5%). The affected patients had a median age of 65 years, and 26 of them (70.3%) were males. Patients with bloodstream infection caused by vancomycin-resistant E. faecium (VREfm) or vancomycin-susceptible E. faecium (VSEfm) showed a similar in-hospital mortality rate (33.3% vs 27.3%, P = 0.692), indicating that VREfm were not more virulent than VSEfm. In contrast, the genetic diversity was higher in VSEfm (15 clonal lineages) than in VREfm isolates (seven clonal lineages). The majority of VREfm isolates (73.2%) belonged to only three clonal lineages: ST117/CT71 vanB ( n = 4), which is the most commonly detected vancomycin-resistant lineage in Germany, and two novel ST1299 vanA lineages classified as CT3109 ( n = 4) and CT1903 ( n = 3). We conclude that the high rate of vancomycin resistance among invasive E. faecium isolates at UKER could be associated with the emergence of novel ST1299 vanA lineages, which is likely to be relevant also for other hospitals and countries. Future studies will focus on the prevalence of ST1299 vanA in the general population. IMPORTANCE The proportion of VREfm among all Enterococcus faecium isolated from blood cultures in German hospitals has increased in the period 2015–2020 from 11.9% to 22.3% with a country-wide spread of the clonal lineage ST117/CT71 vanB . In this study, we provided useful information about the genetic diversity of invasive strains of E. faecium . Moreover, our findings confirm the nosocomial spread of novel ST1299 vanA lineages, which recently had a rapid expansion in Austria and the south-eastern part of Germany. </jats:sec

    Beam characterization and feasibility study for a small animal irradiation platform at clinical proton therapy facilities

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    A deeper understanding of biological mechanisms to promote more efficient treatment strategies in proton therapy demands advances in preclinical radiation research. However this is often limited by insufficient availability of adequate infrastructures for precision image guided small animal proton irradiation. The project SIRMIO aims at filling this gap by developing a portable image-guided research platform for small animal irradiation, to be used at clinical facilities and allowing for a precision similar to a clinical treatment, when scaled down to the small animal size. This work investigates the achievable dosimetric properties of different lowest energy clinical proton therapy beams, manipulated by a dedicated portable beamline including active focusing after initial beam energy degradation and collimation. By measuring the lateral beam size in air close to the beam nozzle exit and the laterally integrated depth dose in water, an analytical beam model based on the beam parameters of the clinical beam at the Rinecker Proton Therapy Center was created for the lowest available clinical beam energy. The same approach was then applied to estimate the lowest energy beam model of different proton therapy facilities, Paul Scherrer Institute, Centre Antoine Lacassagne, Trento Proton Therapy Centre and the Danish Centre for Particle Therapy, based on their available beam commissioning data. This comparison indicated similar beam properties for all investigated sites, with emittance values of a few tens of mm·mrad. Finally, starting from these beam models, we simulated propagation through a novel beamline designed to manipulate the beam energy and size for precise small animal irradiation, and evaluated the resulting dosimetric properties in water. For all investigated initial clinical beams, similar dosimetric results suitable for small animal irradiation were found. This work supports the feasibility of the proposed SIRMIO beamline, promising suitable beam characteristics to allow for precise preclinical irradiation at clinical treatment facilities

    Bewertung von Vogelarten bei der Zulassung von Pestiziden in Europa

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    Es wird eine Übersicht zur Vorgehensweise der Risikobewertung von Vögeln zu potentiell durch Pflanzenschutzmittel auftretenden akuten und reproduktiven Effekten gegeben. Grundlage einer solchen Risikobewertung ist die aktuelle Richtlinie (EFSA 2009) der europäischen Behörde für Lebensmittelsicherheit, EFSA. Nach kurzer Einleitung über die Veränderungen der Zulassungsbestimmungen für Vögel der Agrarlandschaft und Erläutern des grundsätzlichen Prozedere, wird an einem Beispiel eines fiktiven Fungizids eine Risikobewertung exemplarisch aufgezeigt. Grundlagen der derzeitigen Risikobewertung und deren Bewertung durch die Richtlinie werden kurz diskutiert.Stichwörter: Risikobewertung, Pflanzenschutzmittel, VögelAssessing bird species in the registration process of pesticides in EuropeAbstractWe provide an overview and discussion of the methodology currently used to assess the acute and chronic (i.e. reproductive) risk posed by plant protection products to birds. The methodology follows guidance published by the European Food Safety Authority, EFSA (EFSA, 2009). Our overview begins with a short introduction including a brief discussion of recent changes to the regulations on which the EFSA Guidance is based. The standard risk assessment procedure is then explained using the example of a hypothetical fungicide. This is followed by a discussion of the basis, weighting and evaluation of the current risk assessment methodology for birds.Keywords: risk assessment, plant protection products, bird

    Tango Controls and data pipeline for petawatt laser experiments

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    The Centre for Advanced Laser Applications in Garching, Germany, is home to the ATLAS-3000 multi-petawatt laser, dedicated to research on laser particle acceleration and its applications. A control system based on Tango Controls is implemented for both the laser and four experimental areas. The device server approach features high modularity, which, in addition to the hardware control, enables a quick extension of the system and allows for automated data acquisition of the laser parameters and experimental data for each laser shot. In this paper we present an overview of our implementation of the control system, as well as our advances in terms of experimental operation, online supervision and data processing. We also give an outlook on advanced experimental supervision and online data evaluation – where the data can be processed in a pipeline – which is being developed on the basis of this infrastructure

    Weather and Financial Risk-Taking: Is Happiness the Channel?

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    Weather variables, and sunshine in particular, are found to be strongly correlated with financial variables. I consider self-reported happiness as a channel through which sunshine affects financial variables. I examine the influence of happiness on risk-taking behavior by instrumenting individual happiness with regional sunshine, and I find that happy people appear to be more risk-averse in financial decisions, and accordingly choose safer investments. Happy people take more time for making decisions and have more self-control. Happy people also expect to live longer and accordingly seem more concerned about the future than the present, and expect less inflation
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