335 research outputs found
Disordered systems on various time scales: a-Si3B3N7 and homogeneous sintering
Modeling of materials systems for long times commonly requires the use of
separation of time scale methods. We discuss this general approach and present
two example systems, a-Si3B3N7 and the generation of homogeneous sinters.Comment: 22 pages, 7 figure
Intramolecular vibronic dynamics in molecular solids: C60
Vibronic coupling in solid C60 has been investigated with a combination of resonant photoemission spectroscopy (RPES) and resonant inelastic x-ray scattering (RIXS). Excitation as a function of energy within the lowest unoccupied molecular orbital resonance yielded strong oscillations in intensity and dispersion in RPES, and a strong inelastic component in RIXS. Reconciling these two observations establishes that vibronic coupling in this core hole excitation leads to predominantly inelastic scattering and localization of the excited vibrations on the molecule on a femtosecond time scale. The coupling extends throughout the widths of the frontier valence bands.
Invariant Distribution of Promoter Activities in Escherichia coli
Cells need to allocate their limited resources to express a wide range of genes. To understand how Escherichia coli partitions its transcriptional resources between its different promoters, we employ a robotic assay using a comprehensive reporter strain library for E. coli to measure promoter activity on a genomic scale at high-temporal resolution and accuracy. This allows continuous tracking of promoter activity as cells change their growth rate from exponential to stationary phase in different media. We find a heavy-tailed distribution of promoter activities, with promoter activities spanning several orders of magnitude. While the shape of the distribution is almost completely independent of the growth conditions, the identity of the promoters expressed at different levels does depend on them. Translation machinery genes, however, keep the same relative expression levels in the distribution across conditions, and their fractional promoter activity tracks growth rate tightly. We present a simple optimization model for resource allocation which suggests that the observed invariant distributions might maximize growth rate. These invariant features of the distribution of promoter activities may suggest design constraints that shape the allocation of transcriptional resources
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Planning tools and techniques for production evaluation and disassembly
This paper describes the development and implementation of a computerized model to support production planning in a specialized type of remanufacturing facility, the Pantex Plant operated for the US Department of Energy. The model integrates two different production processes (nuclear weapon dismantlement and stockpile evaluation) which use common facilities and personnel, and reflects the interactions of scheduling constraints, material flow constraints and resource availability. These two processes reflect characteristics of flow-shop and job-shop operations in a single facility. Operational results from using the model are also discussed
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Production planning tools and techniques for agile manufacturing
Effective use of resources shared among multiple products or processes is critical for agile manufacturing. This paper describes development and implementation of a computerized model to support production planning in a complex manufacturing system at Pantex Plant. The model integrates two different production processes (nuclear weapon dismantlement and stockpile evaluation) which use common facilities and personnel, and reflects the interactions of scheduling constraints, material flow constraints, and resource availability. These two processes reflect characteristics of flow-shop and job-shop operations in a single facility. Operational results from using the model are also discussed
Cross-border outbreak of listeriosis caused by cold-smoked salmon, revealed by integrated surveillance and whole genome sequencing (WGS), Denmark and France, 2015 to 2017
International audienceIn August 2017, an outbreak of six listeriosis cases in Denmark was traced to cold-smoked salmon, using epidemiological investigations and whole-genome sequencing (WGS) analyses. Exchange of genome sequences allowed identification in France of a food isolate from a salmon-derived product and a human isolate from 2016 within the same cgMLST cluster as the Danish isolates (L2-SL8-ST8-CT771). The salmon product came from a third European Union country. WGS can rapidly link human cases and food isolates across Europe
Hazardous materials management using a Cradle-to-Grave Tracking and Information System (CGTIS)
Hazardous materials management includes interactions among materials, personnel, facilities, hazards, and processes of various groups within a DOE site`s environmental, safety & health (ES&H) and line organizations. Although each group is charged with addressing a particular aspect of these properties and interactions, the information it requires must be gathered into a coherent set of common data for accurate and consistent hazardous material management and regulatory reporting. It is these common data requirements which the Cradle-to-Grave Tracking and Information System (CGTIS) is designed to satisfy. CGTIS collects information at the point at which a process begins or a material enters a facility, and maintains that information, for hazards management and regulatory reporting, throughout the entire life-cycle by providing direct on-line links to a site`s multitude of data bases to bring information together into one common data model
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Hazardous materials management using a Cradle-to-Grave Tracking and Information System (CGTIS)
Hazardous materials management includes interactions among materials, personnel, facilities, hazards, and processes of various groups within a DOE site`s environmental, safety & health (ES&H) and line organizations. Although each group is charged with addressing a particular aspect of these properties and interactions, the information it requires must be gathered into a coherent set of common data for accurate and consistent hazardous material management and regulatory reporting. It is these common data requirements which the Cradle-to-Grave Tracking and Information System (CGTIS) is designed to satisfy. CGTIS collects information at the point at which a process begins or a material enters a facility, and maintains that information, for hazards management and regulatory reporting, throughout the entire life-cycle by providing direct on-line links to a site`s multitude of data bases to bring information together into one common data model
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