14,815 research outputs found

    An Integrated Road Construction and Resource Planning Approach to the Evacuation of Victims From Single Source to Multiple Destinations

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    This paper presents our study on the emergency resource-planning problem, particularly on the development of a new approach to resource planning through contraflow techniques with consideration of the repair of damaged infrastructures. The contraflow technique is aimed at reversing traffic flows in one or more inbound lanes of a divided highway for the outbound direction. As opposed to the current literature, our approach has the following salient points: (1) simultaneous consideration of contraflow and repair of repair of roads; (2) classification of victims in terms of their problems and urgency in sending them to a safe place or place to be treated; and (3) consideration of multiple destinations for victims. A simulated experiment is also described by comparing our approach with some variations of our approach. The experimental results show that our approach can lead to a reduction in evacuation time by more than 50%, as opposed to the original resource operation on the damaged transportation network, and by about 20%, as opposed to the approach with resource replanning (only) on the damaged network. In addition, the multiobjective optimization algorithm to solve our model can be generalized to other network resource-planning problems under infrastructure damage

    Correlation effects in the electronic structure of the Ni-based superconducting KNi2S2

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    Carbapenem resistance in bacteria isolated from soil and water environments in Algeria.

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    This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordOBJECTIVES: Recent research has demonstrated that natural populations of bacteria carry large numbers of mobile genetic elements which may harbour antibiotic resistance determinants. The aim of this study was to investigate carbapenem resistance in Gram negative bacteria isolated from natural environments in Bejaia (Algeria), and determine the horizontal gene transfer potential of a subset of these resistance genes. METHODS: Resistant bacteria were isolated and host identified with MALDI-TOF/16S rRNA sequencing. Resistance gene carriage was investigated using double disc synergy, metallo-β-lactamase (MBL) production tests and PCR screening for carbapenemase resistance genes. To determine potential mobility, conjugation experiments were performed. To identify resistance genes, genomic libraries were constructed, functionally screened; then inserts were sequenced. RESULTS: From soil and water samples, 62 resistant strains were classified as belonging to the Enterobacteriaceae, Pseudomonadaceae, Xanthomonadaceae and Aeromonadaceae families. Four highly imipenem and cefotaxime resistant (MICs >64μg/ml and >8μg/ml, respectively), clinically relevant strains were selected for further characterization. All four strains produced extended spectrum β-lactamases, but MBL production was not confirmed. Imipenem and cefotaxime resistance was transferable to E. coli strains but was not conferred by blaAMPc, blaIMP, blaNDM, blaKPC, blaOXA-48 or blaGES genes. Novel putative resistance mechanisms were identified, including a novel DHA β-lactamase which conferred clinical resistance to cefotaxime. CONCLUSIONS: The environment is a reservoir of carbapenem resistant bacteria. Further investigation of evolution and dissemination of antibiotic resistance in environmental bacteria is required, to understand and prevent the emergence of resistance in clinical environment

    Evacuation Planning Based on the Contraflow Technique With Consideration of Evacuation Priorities and Traffic Setup Time

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    Evacuation planning with the contraflow technique is a complex planning problem. The problem is further complicated when more realistic situations such as evacuation priorities and the setup time for the contraflow operation are considered. Such a complex problem has yet to be discussed in the present literature. In this paper, we present a multipleobjective optimization model for this problem and a two-layer algorithm to solve this model. Experiments on three transportation networks with different network scales are presented to show the excellent performance of the proposed model and algorithm.published_or_final_versio

    Transport and adsorption of antibiotics by marine sediments in a dynamic environment

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    Author name used in this publication: Weihai H. XuAuthor name used in this publication: Onyx W. H. WaiAuthor name used in this publication: Shichun C. ZouAuthor name used in this publication: Xiangdong D. Li2008-2009 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

    Quantifying Rapid Variability in Accreting Compact Objects

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    I discuss some practical aspects of the analysis of millisecond time variability X-ray data obtained from accreting neutron stars and black holes. First I give an account of the statistical methods that are at present commonly applied in this field. These are mostly based on Fourier techniques. To a large extent these methods work well: they give astronomers the answers they need. Then I discuss a number of statistical questions that astronomers don't really know how to solve properly and that statisticians may have ideas about. These questions have to do with the highest and the lowest frequency ranges accessible in the Fourier analysis: how do you determine the shortest time scale present in the variability, how do you measure steep low-frequency noise. The point is stressed that in order for any method that resolves these issues to become popular, it is necessary to retain the capabilities the current methods already have in quantifying the complex, concurrent variability processes characteristic of accreting neutron stars and black holes.Comment: To be published in the Proceedings of "Statistical Challenges in Modern Astronomy II", University Park PA, USA, June 199

    Determination of selected antibiotics in the Victoria Harbour and the Pearl River, South China using high-performance liquid chromatography-electrospray ionization tandem mass spectrometry

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    2006-2007 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

    Evolution of antibiotic resistance at low antibiotic concentrations including selection below the minimal selective concentration

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    This is the final version. Available on open access from Nature Research via the DOI in this recordData availability: The datasets associated with Figs. 1–6 are included in this published article as a Supplementary Data file. Metagenome sequence files have been deposited in the European Nucleotide Archive. Accession number: PRJEB38942.Code availability: Code used for metagenome analysis: FastQC; MultiQC; FLASH2; Metaphlan2; Hclust2 and ARGs-OAP v2.Determining the selective potential of antibiotics at environmental concentrations is critical for designing effective strategies to limit selection for antibiotic resistance. This study determined the minimal selective concentrations (MSCs) for macrolide and fluoroquinolone antibiotics included on the European Commission's Water Framework Directive's priority hazardous substances Watch List. The macrolides demonstrated positive selection for ermF at concentrations 1-2 orders of magnitude greater (>500 and 7.8 and <15.6 µg/L). This highlights the need for compound specific assessment of selective potential. In addition, a sub-MSC selective window defined by the minimal increased persistence concentration (MIPC) is described. Differential rates of negative selection (or persistence) were associated with elevated prevalence relative to the no antibiotic control below the MSC. This increased persistence leads to opportunities for further selection over time and risk of human exposure and environmental transmission.Biotechnology and Biological Sciences Research Council (BBSRC)Natural Environment Research Council (NERC
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