45 research outputs found

    Trapping dust particles in the outer regions of protoplanetary disks

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    In order to explain grain growth to mm sized particles and their retention in outer regions of protoplanetary disks, as it is observed at sub-mm and mm wavelengths, we investigate if strong inhomogeneities in the gas density profiles can slow down excessive radial drift and can help dust particles to grow. We use coagulation/fragmentation and disk-structure models, to simulate the evolution of dust in a bumpy surface density profile which we mimic with a sinusoidal disturbance. For different values of the amplitude and length scale of the bumps, we investigate the ability of this model to produce and retain large particles on million years time scales. In addition, we introduced a comparison between the pressure inhomogeneities considered in this work and the pressure profiles that come from magnetorotational instability. Using the Common Astronomy Software Applications ALMA simulator, we study if there are observational signatures of these pressure inhomogeneities that can be seen with ALMA. We present the favorable conditions to trap dust particles and the corresponding calculations predicting the spectral slope in the mm-wavelength range, to compare with current observations. Finally we present simulated images using different antenna configurations of ALMA at different frequencies, to show that the ring structures will be detectable at the distances of the Taurus Auriga or Ophiucus star forming regions.Comment: Pages 15, Figures 14. Accepted for publication in Astronomy and Astrophysic

    An Approach Merging the IDM-Related Knowledge

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    Patents are one of the main innovation knowledge sources for engineers and companies. Inventive Design Method (IDM) – results from a research that extends from TRIZ and contains formal knowledge description components using ontologies, such as problems, partial solutions, and parameters. In this paper, we introduce IDM-Similar model that extends existing research work in IDM-related knowledge. A neural network named Word2vec and cosine similarity approach are used to build this model to compute the similarity among problems in wide range domains’ patents covering from the chemistry to mechanics and the computer to physics. Our model assumes that a partial solution of a patent could be used to solve the problem of another patent from a different domain if these two problems are similar enough. Experiments show that our model is a promising alternative to classical TRIZ for engineers to associate their problems in a field to solutions from patents of another field. Consequently, the step dedicated to solution concepts ideation is improved using our work

    Antimicrobial consumption and resistance in adult hospital inpatients in 53 countries:results of an internet-based global point prevalence survey

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    Summary: Background: The Global Point Prevalence Survey (Global-PPS) established an international network of hospitals to measure antimicrobial prescribing and resistance worldwide. We aimed to assess antimicrobial prescribing and resistance in hospital inpatients. Methods: We used a standardised surveillance method to collect detailed data about antimicrobial prescribing and resistance from hospitals worldwide, which were grouped by UN region. The internet-based survey included all inpatients (adults, children, and neonates) receiving an antimicrobial who were on the ward at 0800 h on one specific day between January and September, 2015. Hospitals were classified as primary, secondary, tertiary (including infectious diseases hospitals), and paediatric hospitals. Five main ward types were defined: medical wards, surgical wards, intensive-care units, haematology oncology wards, and medical transplantation (bone marrow or solid transplants) wards. Data recorded included patient characteristics, antimicrobials received, diagnosis, therapeutic indication according to predefined lists, and markers of prescribing quality (eg, whether a stop or review date were recorded, and whether local prescribing guidelines existed and were adhered to). We report findings for adult inpatients. Findings: The Global-PPS for 2015 included adult data from 303 hospitals in 53 countries, including eight lower-middle-income and 17 upper-middle-income countries. 86 776 inpatients were admitted to 3315 adult wards, of whom 29 891 (34·4%) received at least one antimicrobial. 41 213 antimicrobial prescriptions were issued, of which 36 792 (89·3%) were antibacterial agents for systemic use. The top three antibiotics prescribed worldwide were penicillins with β-lactamase inhibitors, third-generation cephalosporins, and fluoroquinolones. Carbapenems were most frequently prescribed in Latin America and west and central Asia. Of patients who received at least one antimicrobial, 5926 (19·8%) received a targeted antibacterial treatment for systemic use, and 1769 (5·9%) received a treatment targeting at least one multidrug-resistant organism. The frequency of health-care-associated infections was highest in Latin America (1518 [11·9%]) and east and south Asia (5363 [10·1%]). Overall, the reason for treatment was recorded in 31 694 (76·9%) of antimicrobial prescriptions, and a stop or review date in 15 778 (38·3%). Local antibiotic guidelines were missing for 7050 (19·2%) of the 36 792 antibiotic prescriptions, and guideline compliance was 77·4%. Interpretation: The Global-PPS showed that worldwide surveillance can be accomplished with voluntary participation. It provided quantifiable measures to assess and compare the quantity and quality of antibiotic prescribing and resistance in hospital patients worldwide. These data will help to improve the quality of antibiotic prescribing through education and practice changes, particularly in low-income and middle-income countries that have no tools to monitor antibiotic prescribing in hospitals. Funding: bioMérieux

    CONFLICT RESOLUTION, PUBLIC GOODS AND PATENT THICKETS

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    Post-grant validity challenges at patent offices rely on the private initiative of third parties to correct mistakes made by patent offices. We hypothesize that incentives to bring post-grant validity challenges are reduced when many firms benefit from revocation of a patent and when firms are caught up in patent thickets. Using data on opposition against patents at the European Patent Office we show that opposition decreases in fields in which many others profit from patent revocations. Moreover, in fields with a large number of mutually blocking patents the incidence of opposition is sharply reduced, particularly among large firms and firms that are caught up directly in patent thickets. These findings indicate that post-grant patent review may not constitute an effective correction device for erroneous patent grants in technologies affected by either patent thickets or highly dispersed patent ownership

    Domain Study 'Biotechnology'

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    Development of quality indicators for antimicrobial stewardship in Belgian hospitals: a RAND - modified Delphi procedure.

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    Inappropriate antibiotic use is a major cause of antibiotic resistance. Therefore, optimizing antibiotic usage is essential. In Belgium, optimization of antimicrobials for the fight against multidrug resistant organisms (MDROs) is followed up by national surveillance by public health authorities. To improve appropriate antimicrobial use in hospitals, an effective national Antimicrobial Stewardship (AMS) program should include indicators for measuring both the quantity and quality of antibiotic use. The aim of this study was to develop a set of process quality indicators (QIs) to evaluate and improve AMS in hospitals. A RAND-modified Delphi procedure was used. The procedure consisted of a structured narrative literature review to select the QIs, followed by two online questionnaires and an intermediate multidisciplinary panel discussion with experts in infectious diseases from general and teaching hospitals in Belgium. A total of 38 QIs were selected after the RAND-modified Delphi procedure, from which 11 QIs were selected unanimously. These QIs address compliancy of antibiotic therapy and prophylaxis with local guidelines, documentation of the rationale for antibiotic treatment in the medical record, the availability of AMS Programs and Outpatient Parenteral Antibiotic Therapy, resistance patterns and antimicrobial prescribing during focused ward rounds. Our study selected 38 relevant process QIs, from which 11 were unanimously selected. The QIs can contribute to the improvement of quality of antibiotic use by stimulating hospitals to present better outcomes and by providing a focus on how to intervene and to improve prescribing of antimicrobials
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