182 research outputs found

    The RETRIEVE checklist for studies reporting the elicitation of stated preferences for child health related quality of life

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    Recent systematic reviews show varying methods for eliciting, modelling, and reporting preference-based values for child health-related quality-of-life (HRQoL) outcomes, producing value-sets with different characteristics. Checklists can improve standards of reporting; however, existing checklists do not address methodological issues for valuing child HRQoL. We aimed to develop a checklist for studies generating values for child HRQoL, including for disease-specific states and value-sets for generic child HRQoL instruments. A conceptual model provided a structure for grouping items into five modules. Potential items were sourced from an adult HRQoL checklist review, with additional items specific to children developed using recent reviews. Checklist items were reduced by eliminating duplication and overlap, then refined for relevance and clarity via an iterative process. Long and short checklist versions were produced for different user needs. The resulting long RETRIEVE contains 83 items, with modules for reporting methods (A-D) and characteristics of values (E), for researchers planning and reporting child health valuation studies. The short RETRIEVE contains 14 items for decision-makers or researchers choosing value-sets. Applying the RETRIEVE checklists to relevant studies suggests feasibility. RETRIEVE has the potential to improve completeness in the reporting of preference-based values for child HRQOL outcomes and to improve assessment of preference-based value-sets

    A Gene Regulatory Network for Root Epidermis Cell Differentiation in Arabidopsis

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    The root epidermis of Arabidopsis provides an exceptional model for studying the molecular basis of cell fate and differentiation. To obtain a systems-level view of root epidermal cell differentiation, we used a genome-wide transcriptome approach to define and organize a large set of genes into a transcriptional regulatory network. Using cell fate mutants that produce only one of the two epidermal cell types, together with fluorescence-activated cell-sorting to preferentially analyze the root epidermis transcriptome, we identified 1,582 genes differentially expressed in the root-hair or non-hair cell types, including a set of 208 “core” root epidermal genes. The organization of the core genes into a network was accomplished by using 17 distinct root epidermis mutants and 2 hormone treatments to perturb the system and assess the effects on each gene's transcript accumulation. In addition, temporal gene expression information from a developmental time series dataset and predicted gene associations derived from a Bayesian modeling approach were used to aid the positioning of genes within the network. Further, a detailed functional analysis of likely bHLH regulatory genes within the network, including MYC1, bHLH54, bHLH66, and bHLH82, showed that three distinct subfamilies of bHLH proteins participate in root epidermis development in a stage-specific manner. The integration of genetic, genomic, and computational analyses provides a new view of the composition, architecture, and logic of the root epidermal transcriptional network, and it demonstrates the utility of a comprehensive systems approach for dissecting a complex regulatory network

    Rocket propellant combustion studies in a constant volume bomb

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    A constant volume window bomb has been used to measure the characteristic velocity (c∗ ) of rocket propellants. Analysis of the combustion process inside the bomb including heat losses has been made. The experiments on double base and composite propellants have revealed some (i) basic heat transfer aspects inside the bomb and (ii) combustion characteristics of Ammonium Perchlorate-Polyester propellants. It has been found that combustion continues even beyond the peak pressure and temperature points. Lithium Fluoride mixed propellants do not seem to indicate significant differences in c∗ ) though the low pressure deflagration limit is increased with percentage of Lithium Fluoride

    Jet Interaction in Liquid-Liquid Coaxial Injectors

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