431 research outputs found

    Acoustic Array Measurements of a 1:10.6 Scaled Airbus A340 Model

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    Understanding phoneme segmentation performance by analyzing abilities and word properties

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    Several studies have demonstrated the relationship between phoneme segmentation ability and early reading performance, but so far it is unclear which abilities are involved, and which word properties contribute to the difficulty level of a segmentation task. Using a sample of 596 Dutch children, we investigated the abilities involved in segmenting the phonemes of 45 pseudowords that differed with respect to several properties. First, we found that a combination of short-term memory and speech perception explained variation in segmentation performance. Second, we found that a limited number of word property effects explained the difficulty level of pseudowords rather well. Finally, we constructed a high-reliability scale for measuring segmentation ability. </jats:p

    Inversion of spinning sound fields

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    A method is presented for the reconstruction of rotating monopole source distributions using acoustic pressures measured on a sideline parallel to the source axis. The method requires no \textit{a priori} assumptions about the source other than that its strength at the frequency of interest vary sinusoidally in azimuth on the source disc so that the radiated acoustic field is composed of a single circumferential mode. When multiple azimuthal modes are present, the acoustic field can be decomposed into azimuthal modes and the method applied to each mode in sequence. The method proceeds in two stages, first finding an intermediate line source derived from the source distribution and then inverting this line source to find the radial variation of source strength. A far-field form of the radiation integrals is derived, showing that the far field pressure is a band-limited Fourier transform of the line source, establishing a limit on the quality of source reconstruction which can be achieved using far-field measurements. The method is applied to simulated data representing wind-tunnel testing of a ducted rotor system (tip Mach number~0.74) and to control of noise from an automotive cooling fan (tip Mach number~0.14), studies which have appeared in the literature of source identification.Comment: Revised version of paper submitted to JASA; five more figures; expanded content with more discussion of error behaviour and relation to Nearfield Acoustical Holograph

    Development and individual differences in transitive reasoning: A fuzzy trace theory approach

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    Fuzzy trace theory explains why children do not have to use rules of logic or premise information to infer transitive relationships. Instead, memory of the premises and performance on transitivity tasks is explained by a verbatim ability and a gist ability. Until recently, the processes involved in transitive reasoning and memory of the premises were studied by comparing mean performance in fixed-age groups. In this study, an individual-difference model of fuzzy trace theory for transitive reasoning was formulated and tested on a sample (N = 409) of 4- to 13-year-old children. Tasks were used which differed with respect to presentation ordering and position ordering. From this individual- difference model expectations could be derived about the individual performance on memory and transitivity test-pairs. The multilevel latent class model was used to fit the formalized individual-difference fuzzy trace theory to the sample data. The model was shown to fit the data to a large extent. The results showed that verbatim ability and gist ability drove the activation of verbatim and gist traces, respectively, and that children used combinations of these traces to solve memory tasks (testing memory of the premises) and transitivity tasks. Task format had a stronger effect on transitivity task performance than on memory of the premises. Development of gist ability was found to be faster than development of verbatim ability. Another important finding was that some children remembered the premise information correctly but were not able to infer the transitive relationship, even though the premises provided all the necessary information. This contradicts Trabasso’s linear ordering theory which posits that memory of the premises is sufficient to infer transitive relationships

    Understanding the Role of Nature in Urban-Rural Linkages: Identifying the Potential Role of Rural Nature-Based Attractive Clusters That Serve Human Well-Being

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    Rural areas provide unique amenities for recreational purposes which are highly appreciated by urban inhabitants. This generates an important but often hidden relationship between the urban and the rural. The aim of our study is first to provide empirical evidence for this linkage and then to identify for Italy, at the municipal level, those rural areas which actually function as nature-based attractive clusters. We used the data coming from a participatory webGIS survey that asked 1632 Italian respondents to mark attractive nature related places locally, regionally, nationally and world-wide to explain quantitatively and qualitatively the relationship between urban and rural. From the survey, indicators were developed to rank the nature-based attractive clusters. Our results pointed out a major (almost double) flow from urban to rural for natural amenities, which increased with the spatial level at which attractive nature areas were marked. This analysis allowed for the identification rural clusters of Italian municipalities that form nodal points for nature-based urban well-being; shedding light on an often neglected urban-rural relationship. The method is applicable in other countries and may stimulate better planning and management strategies for improving rural areas, taking an urban-rural perspective

    The Attitudes to Ageing Questionnaire:Mokken Scaling Analysis

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    BACKGROUND:Hierarchical scales are useful in understanding the structure of underlying latent traits in many questionnaires. The Attitudes to Ageing Questionnaire (AAQ) explored the attitudes to ageing of older people themselves, and originally described three distinct subscales: (1) Psychosocial Loss (2) Physical Change and (3) Psychological Growth. This study aimed to use Mokken analysis, a method of Item Response Theory, to test for hierarchies within the AAQ and to explore how these relate to underlying latent traits. METHODS:Participants in a longitudinal cohort study, the Lothian Birth Cohort 1936, completed a cross-sectional postal survey. Data from 802 participants were analysed using Mokken Scaling analysis. These results were compared with factor analysis using exploratory structural equation modelling. RESULTS:Participants were 51.6% male, mean age 74.0 years (SD 0.28). Three scales were identified from 18 of the 24 items: two weak Mokken scales and one moderate Mokken scale. (1) 'Vitality' contained a combination of items from all three previously determined factors of the AAQ, with a hierarchy from physical to psychosocial; (2) 'Legacy' contained items exclusively from the Psychological Growth scale, with a hierarchy from individual contributions to passing things on; (3) 'Exclusion' contained items from the Psychosocial Loss scale, with a hierarchy from general to specific instances. All of the scales were reliable and statistically significant with 'Legacy' showing invariant item ordering. The scales correlate as expected with personality, anxiety and depression. Exploratory SEM mostly confirmed the original factor structure. CONCLUSIONS:The concurrent use of factor analysis and Mokken scaling provides additional information about the AAQ. The previously-described factor structure is mostly confirmed. Mokken scaling identifies a new factor relating to vitality, and a hierarchy of responses within three separate scales, referring to vitality, legacy and exclusion. This shows what older people themselves consider important regarding their own ageing

    Update of the list of qualified presumption of safety (QPS) recommended microorganisms intentionally added to food or feed as notified to EFSA

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    The qualified presumption of safety (QPS) provides a generic pre-assessment of the safety ofmicroorganisms intended for use in the food or feed chains, to support the work of EFSA’s ScientificPanels. QPS assessment allows a fast track evaluation of strains belonging to QPS taxonomic units(TUs): species for bacteria, yeast, fungi, protists/microalgae and families for viruses. QPS TUs areassessed for their body of knowledge and safety. Safety concerns related to a QPS TU are reflected,when possible, as‘qualifications’, which should be tested at strain and/or product level. Based on thepossession of potentially harmful traits by some strains,filamentous fungi, bacteriophages, oomycetes,streptomycetes,Enterococcus faecium,Escherichia coliandClostridium butyricumare excluded fromthe QPS assessment.Between October 2019 and September 2022, 323 notifications of TUs werereceived, 217 related to feed additives, 54 to food enzymes, food additives andflavourings, 14 to plantprotection products and 38 to novel foods. The list of QPS-recommended TUs is reviewed every6 months following an extensive literature search strategy. Only sporadic infections with a few QPSstatus TUs in immunosuppressed individuals were identified and the assessment did not change theQPS status of these TUs. The QPS list has been updated in relation to the most recent taxonomicinsights and the qualifications were revised and streamlined. The qualification‘absence ofaminoglycoside production ability’was withdrawn forBacillus velezensis. Six new TUs received the QPSstatus:Bacillus paralicheniformiswith the qualification‘absence of toxigenic activity’and‘absence ofbacitracin production ability’;Bacillus circulanswith the qualifications for‘production purposes only’and‘absence of cytotoxic activity’;Haematococcus lacustris(synonymHaematococcus pluvialis) andOgataea polymorpha, both with the qualification‘for production purposes only’;Lactiplantibacillusargentoratensis;Geobacillus thermodenitrificanswith the qualification‘absence of toxigenic activity
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