185 research outputs found

    Normal mode analysis of a rotating group of lashed turbine blades by substructures

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    A group of 5 lashed identical stream turbine blades is studied through the use of single level substructuring using NASTRAN level 15.1. An altered version, similar to DMAP Program Number 3 of the NASTRAN Newsletter, of Rigid Format 13.0 was used. Steady-state displacements and stresses due to centrifugal loads are obtained both without and with consideration of differential stiffness. The normal mode calculations were performed for blades at rest and at operating speed. Substructuring lowered the computation costs of the analysis by a factor of four

    Placing three-dimensional isoparametric elements into NASTRAN

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    Linear (8 node), parabolic (20 node), cubic (32 node) and mixed (some edges linear, some parabolic and some cubic) have been inserted into NASTRAN, level 15.1. First the dummy element feature was used to check out the stiffness matrix generation routines for the linear element in NASTRAN. Then, the necessary modules of NASTRAN were modified to include the new family of elements. The matrix assembly was changed so that the stiffness matrix of each isoparametric element is only generated once as the time to generate these higher order elements tends to be much longer than the other elements in NASTRAN. This paper presents some of the experiences and difficulties of inserting a new element or family of elements into NASTRAN

    The Music in \u3ci\u3eHis\u3c/i\u3e Words: The Art of Sound and Folk in Louis Armstrong’s Manuscript for \u3ci\u3eSatchmo: My Life in New Orleans\u3c/i\u3e, “The Armstrong Story”

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    This thesis dives into the musical journey embedded in the autobiographical writings of America’s jazz ambassador, Louis Armstrong. It examines Armstrong’s typewritten manuscript, The Armstrong Story, which was eventually revised by an editor and published as his second autobiography with the title of Satchmo: My Life in New Orleans in 1954 (originally published in France in 1952.) Armstrong’s manuscript reads like sheet music, where any sound could affect the harmony of the story. He created a voice that had met every art form before it became the manuscript of his autobiography, but along with that voice, references from Black folk and orality were removed by the editor from the published version, separating it from similar works of his time that treasured these features especially. The original manuscript in the Louis Armstrong House Museum Archives bears visual marks, auto-edits, and a dramatic punctuation, providing a layer of meanings and signifiers missing in the published autobiography. His notes outside the manuscript margins tell of an artist on the road; a star living the luxurious minutes of his privacy in front of a typewriter; an ordinary man at his beloved home, a celebrity at the peak of fame, but most importantly they tell of the Black twentieth century genius in the conscious act of introducing folk elements with a transnational impact. Armstrong had elevated these elements in music by delivering traditional songs with virtuosity and versatility, and he had a studious affinity for other essentially traditional songs that had already reached universality like opera or indigenous rhythms. This manuscript is the only one closer to his style that was published while the author was alive. His first, Swing that Music (1936), was heavily edited. This research places the manuscript’s relevance in the study of autobiography: in a larger scope, it intends to classify this example, and other similar cases, when an author’s style has meaning in and of itself, which may have become lost because of editing for publication; in a narrower focus, it expands Armstrong scholarship by highlighting his autobiography’s ontological, anthropological and historic value. Before writing this book, Armstrong had already offered groundbreaking contributions to music with his instrumental and vocal styles, and he brought with him hundreds of references to his New Orleans folk culture, that proved then to challenge the racially integrated society of the 1950s. Referring to Armstrong’s scat singing, Jazz critic Gary Giddins says in Visions of Jazz, “he added scat’s moans and riffs to the palette of conventional song interpretation, employing them to underscore emotion and rhythm and meaning” (86). His writing inherits the form and characters from those “moans and riffs.” It underscores –on the paper as well— “emotion, and rhythm, and meaning”, but its literary value was over-shadowed by his celebrity. New Orleans culture provides a precedent for a writing style that privileges sound, and a narrative that intends to document folk traditions. Deeply rooted in rhythm, a writing style is created from the sound of words – ‘Who dat?’— But Armstrong went further, making a language of his own. It would be inaccurate to call Armstrong’s writing solely a reflection of slang or Black speech. Armstrong used ‘Jive’ talk and jazz music as a compositional style in his lines. He could speak music in a sigh. Armstrong’s is an ideal American success story told in the spirit of Black folk, but that spirit, which brings a much deeper and symbolic legacy, is left on the surface due to his immersion in the mainstream. This thesis identifies an iconic achievement of creative individuality by Armstrong, a Black artist, and proposes a new interpretation of his manuscript that better reads his intentions of preserving folk traditions while making them relevant globally

    Approaches for advancing scientific understanding of macrosystems

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    The emergence of macrosystems ecology (MSE), which focuses on regional- to continental-scale ecological patterns and processes, builds upon a history of long-term and broad-scale studies in ecology. Scientists face the difficulty of integrating the many elements that make up macrosystems, which consist of hierarchical processes at interacting spatial and temporal scales. Researchers must also identify the most relevant scales and variables to be considered, the required data resources, and the appropriate study design to provide the proper inferences. The large volumes of multi-thematic data often associated with macrosystem studies typically require validation, standardization, and assimilation. Finally, analytical approaches need to describe how cross-scale and hierarchical dynamics and interactions relate to macroscale phenomena. Here, we elaborate on some key methodological challenges of MSE research and discuss existing and novel approaches to meet them

    Biodiversity change is uncoupled from species richness trends: consequences for conservation and monitoring

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    Global concern about human impact on biological diversity has triggered an intense research agenda on drivers and consequences of biodiversity change in parallel with international policy seeking to conserve biodiversity and associated ecosystem functions. Quantifying the trends in biodiversity is far from trivial, however, as recently documented by meta-analyses, which report little if any net change in local species richness through time. Here, we summarise several limitations of species richness as a metric of biodiversity change and show that the expectation of directional species richness trends under changing conditions is invalid. Instead, we illustrate how a set of species turnover indices provide more information content regarding temporal trends in biodiversity, as they reflect how dominance and identity shift in communities over time. We apply these metrics to three monitoring datasets representing different ecosystem types. In all datasets, nearly complete species turnover occurred, but this was disconnected from any species richness trends. Instead, turnover was strongly influenced by changes in species presence (identities) and dominance (abundances). We further show that these metrics can detect phases of strong compositional shifts in monitoring data and thus identify a different aspect of biodiversity change decoupled from species richness. Synthesis and applications: Temporal trends in species richness are insufficient to capture key changes in biodiversity in changing environments. In fact, reductions in environmental quality can lead to transient increases in species richness if immigration or extinction has different temporal dynamics. Thus, biodiversity monitoring programmes need to go beyond analyses of trends in richness in favour of more meaningful assessments of biodiversity change

    Objective, Subjective, and Self-Assessment of Preadolescent Orthodontic Treatment Need – A Function of Age, Gender, and Ethnic/Racial Background?

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    Children from socioeconomically disadvantaged and/or underrepresented minority backgrounds in the United States have limited or no access to orthodontic treatment. Objectives: To determine whether preadolescents' (a) objectively assessed orthodontic treatment need; (b) subjectively assessed orthodontic treatment need; and (c) self-perceptions of the psychologic aspects of their oral health-related quality of life and desire to have braces vary as a function of age, gender, ethnicity/race, and socioeconomic status (SES). Methods: Data were collected from 1,566 preadolescents (age range: 8 to 11 years; 47.3 percent male/52.7 percent female; 55.7 percent African-American/39.7 percent White/2.9 percent Hispanic) in oral exams and in face to face interviews. Malocclusion was determined with the Index of Orthodontic Treatment Need. Results: Children (17.2 percent) had definite treatment need, 33.7 percent were borderline, and 49.1 percent had little or no need. Objectively and subjectively assessed treatment need was not affected by the children's age or gender. However, girls were more critical of their smiles and wanted braces more than boys. The older the children were, the more critical they were and the more they wanted braces. African-American children and children in schools with higher percentages of children on free school lunches had less treatment need than White children and children in schools with lower percentages of students with free school lunches. While the provider-assessed treatment need was higher for White children than for Black children, Black children were less happy with their smiles than White children, and wanted braces more than White children. SES did not affect the children's self-perceptions. Conclusions: Findings showed that substantial percentages of the preadolescents have an orthodontic treatment need. Orthodontic need and child self-perceptions varied as a function of the children's age, gender, ethnicity/race, and SES.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65150/1/j.1752-7325.2008.00089.x.pd

    Parental perceptions of children's oral health: The Early Childhood Oral Health Impact Scale (ECOHIS)

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    BACKGROUND: Dental disease and treatment experience can negatively affect the oral health related quality of life (OHRQL) of preschool aged children and their caregivers. Currently no valid and reliable instrument is available to measure these negative influences in very young children. The objective of this research was to develop the Early Childhood Oral Health Impact Scale (ECOHIS) to measure the OHRQL of preschool children and their families. METHODS: Twenty-two health professionals evaluated a pool of 45 items that assess the impact of oral health problems on 6-14-year-old children and their families. The health professionals identified 36 items as relevant to preschool children. Thirty parents rated the importance of these 36 items to preschool children; 13 (9 child and 4 family) items were considered important. The 13-item ECOHIS was administered to 295 parents of 5-year-old children to assess construct validity and internal consistency reliability (using Cronbach's alpha). Test-retest reliability was evaluated among another sample of parents (N = 46) using the intraclass correlation coefficient (ICC). RESULTS: ECOHIS scores on the child and parent sections indicating worse quality of life were significantly associated with fair or poor parental ratings of their child's general and oral health, and the presence of dental disease in the child. Cronbach's alphas for the child and family sections were 0.91 and 0.95 respectively, and the ICC for test-retest reliability was 0.84. CONCLUSION: The ECOHIS performed well in assessing OHRQL among children and their families. Studies in other populations are needed to further establish the instrument's technical properties

    Approaches to advance scientific understanding of macrosystems ecology

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    The emergence of macrosystems ecology (MSE), which focuses on regional- to continental-scale ecological pat- terns and processes, builds upon a history of long-term and broad-scale studies in ecology. Scientists face the difficulty of integrating the many elements that make up macrosystems, which consist of hierarchical processes at interacting spatial and temporal scales. Researchers must also identify the most relevant scales and variables to be considered, the required data resources, and the appropriate study design to provide the proper inferences. The large volumes of multi-thematic data often associated with macrosystem studies typically require valida- tion, standardization, and assimilation. Finally, analytical approaches need to describe how cross-scale and hierarchical dynamics and interactions relate to macroscale phenomena. Here, we elaborate on some key methodological challenges of MSE research and discuss existing and novel approaches to meet them

    Validation of a Farsi version of the Early Childhood Oral Health Impact Scale (F-ECOHIS)

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    <p>Abstract</p> <p>Background</p> <p>The Early Childhood Oral Health Impact Scale (ECOHIS) has recently been developed to assess oral health-related quality of life (OHRQoL) of pre-school children in English speaking communities. This study aimed to translate the ECOHIS into Farsi and test its psychometric properties for use on 2- to 5-year-old children of Farsi speaking Iranian families.</p> <p>Methods</p> <p>EHOHIS questionnaire was translated into Farsi using a standardized forward-backward linguistic translation method. Its face and content validity was tested in two small pilot studies. In the main study, a convenience sample of 260 parents of 2- to 5-year-old children in Isfahan and Tehran were invited to complete the final Farsi version of the ECOHIS (F-ECOHIS) and answer two global self-rating questions about their children's dental appearance and oral health. Association between F-ECOHIS scores and answers to the two self-rating questions, and the correlation between child (9 items) and family (4 items) sections of the F-ECOHIS were used to assess the concurrent and convergent validity of the questionnaire. Internal consistency reliability of the F-ECOHIS was tested using Cronbach's alpha coefficient test and item total and inter-item correlations. One third of participants were invited to complete the F-ECOHIS again after 2 weeks to evaluate the test-retest reliability of the questionnaire.</p> <p>Results</p> <p>Two hundred and forty six parents were included in the main study. The association between the F-ECOHIS scores and the two self-rating questions and the correlation between its child and family sections were significant (P < 0.001). Cronbach's alpha coefficient of the F-ECOHIS and its child and family sections were 0.93, 0.89, and 0.85 respectively. Coefficients did not increase by deleting any item. The corrected item total correlation coefficient ranged from 0.52 to 0.74. The inter-item correlation coefficient ranged between 0.30 and 0.73. Seventy three parents participated in the follow up study for re-testing the questionnaire. Comparison of their test and re-test scores had a weighted kappa of 0.81 and inter-class correlation (ICC) of 0.82.</p> <p>Conclusion</p> <p>The F-ECOHIS questionnaire was valid and reliable for assessing the OHRQoL of 2- to 5-year-old pre-school children of Farsi speaking parents.</p
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