289 research outputs found
Spiral FFAG lattice design tools - Application to 6-D tracking
Ray-tracing based methods for 3-D modeling of magnetic field and particle motion in spiral scaling FFAG accelerators have been developed. They allow efficient simulation of particle motion in presence of the strong field non-linearities proper to FFAG magnets, and of possible field overlapping in configurations of neighboring magnets, thus yielding a performing tool for spiral FFAG lattice design and optimizations, and for 6-D tracking studies. It is applied for illustration to a principle design of a 200 MeV medical class proton FFAG now under study in the frame of the RACCAM hadrontherapy project
Symmetry and reciprocity constraints on diffraction by gratings of quasi-planar particles
Symmetry and reciprocity constraints on polarization state of the field
diffracted by gratings of quasi-planar particles are considered. It is shown
that the optical activity effects observed recently in arrays of quasi-planar
plasmonic particles on a dielectric substrate are due to the reflection of the
field at the air-dielectric slab interface and are proportional to this
reflection coefficient.Comment: 11 pages, 3 figures, 12 references; minor corrections for better
appearanc
The FFAG R&D and medical application project RACCAM
JACoW web site http://accelconf.web.cern.ch/AccelConf/e06/Pre-Press/WEPCH161.pdf WEPCH161International audienceThe RACCAM project (Recherche en ACCelerateurs et Applications Medicales) has recently obtained fundings, extending over three years (2006-2008), from the French National Research Agency (ANR). RACCAM is a tripartite collaboration, involving (i) the CNRS Laboratory IN2P3/LPSC, (ii) the French magnet industrial SIGMAPHI, and (iii) the nuclear medecine Departement of Grenoble Hospital. The project concerns fixed field alternating gradient accelerator (FFAG) research on the one hand, and on the other hand their application as hadrontherapy and biology research machines. RACCAM's goal is three-fold, (i) participate to the on-going international collaborations in the field of FFAGs and recent concepts of "non-scaling" FFAGs, with frames for instance, the Neutrino Factory (NuFact) and the EMMA project of an electron model of a muon FFAG accelerator, (ii) design, build and experiment a prototype of an FFAG magnet proper to fulfil the requirements of rapid cycling acceleration, (iii) develop the concepts, and show the feasibility, of the application of such FFAG beams to hadrontherapy and to biology research
Cardiovascular and Gastrointestinal Safety of NSAIDs: a Systematic Review of Meta-Analyses of Randomized Clinical Trials.
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Mechanisms of failure to decontaminate the gut with polymixin E, gentamicin and amphotericin B in patients in intensive care.
The objective of the present work was to assess the possible mechanisms of the poor efficiency of selective decontamination of the digestive tract (SDD) in medical and surgical intensive care unit (ICU) patients. Sixty-four consecutive mechanically ventilated patients received gut decontamination with polymixin E, gentamicin and amphotericin B via a nasogastric tube and were assessed for oropharyngeal, gastric and fecal colonization and for the presence of each antibiotic in the stomach and feces. A decrease in fecal colonization with Escherichia coli was observed over 20 days but not with other gram-negative bacteria or gram-positive cocci. Fifteen and 26% of the fecal colonizing gram-negative bacteria were resistant to polymixin E and gentamicin, respectively, at admission. These proportions increased to up to 50% after 16 days of treatment. Although 50% of staphylococci were initially sensitive to gentamicin, all strains were resistant to this drug after four days of SDD. Both antibiotics were found in concentrations of less than 20 micrograms/g in 11 of 38 stools. Of these 38 stools, nine were not contaminated, 20 were colonized with resistant bacteria and 16 with strains sensitive to one antibiotic present in the stool. Therefore, the poor efficiency of gut decontamination observed was probably due to the great proportion of resistant strains on admission of the patients, to the selection of such resistant strains with SDD, to poor intestinal transit of the antibiotics, and to inactivation of the drugs by the feces. These results support stringent monitoring of fecal colonization in patients undergoing SDD in order to detect the fecal carriage of gram-positive and multiresistant gram-negative bacteria
Mesoscale Modelling of Woven Composite Materials with Manufacturing Defect Using Micro-Tomography Images
Spiral FFAG for protontherapy
International audienceHigh repetition rate of the FFAG accelerator and compactness of the spiral type of the design makes it a good candidate as medical machine for protontherapy and biological research. The variable energy extraction with various methods is discussed. The principle of the lattice design together with injection scheme and the beam dynamics simulations are presented. The spiral magnet design undertaken in the frame of the RACCAM project is briefly described
Singularities and Topology of Meromorphic Functions
We present several aspects of the "topology of meromorphic functions", which
we conceive as a general theory which includes the topology of holomorphic
functions, the topology of pencils on quasi-projective spaces and the topology
of polynomial functions.Comment: 21 pages, 1 figur
Open-access platform to synthesize knowledge of ape conservation across sites
Despite the large body of literature on ape conservation, much of the data needed for evidenceâbased conservation decisionâmaking is still not readily accessible and standardized, rendering crossâsite comparison difficult. To support knowledge synthesis and to complement the IUCN SSC Ape Populations, Environments and Surveys database, we created the A.P.E.S. Wiki (https://apeswiki.eva.mpg.de), an openâaccess platform providing siteâlevel information on ape conservation status and context. The aim of this Wiki is to provide information and data about geographical ape locations, to curate information on individuals and organizations active in ape research and conservation, and to act as a tool to support collaboration between conservation practitioners, scientists, and other stakeholders. To illustrate the process and benefits of knowledge synthesis, we used the momentum of the update of the conservation action plan for western chimpanzees (Pan troglodytes verus) and began with this critically endangered taxon. First, we gathered information on 59 sites in West Africa from scientific publications, reports, and online sources. Information was compiled in a standardized format and can thus be summarized using a web scraping approach. We then asked experts working at those sites to review and complement the information (20 sites have been reviewed to date). We demonstrate the utility of the information available through the Wiki, for example, for studying species distribution. Importantly, as an openâaccess platform and based on the wellâknown wiki layout, the A.P.E.S. Wiki can contribute to direct and interactive information sharing and promote the efforts invested by the ape research and conservation community. The Section on Great Apes and the Section on Small Apes of the IUCN SSC Primate Specialist Group will guide and support the expansion of the platform to all small and great ape taxa. Similar collaborative efforts can contribute to extending knowledge synthesis to all nonhuman primate species
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