1,720,968 research outputs found

    Development of an Exhaust System for Agricultural Tractors

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    The main sources of sound emitted by vehicles are the engine and the rolling noise produced by the tires. In case agricultural tractors are considered, the engine and the transmission are responsible of the main emissions since they often work in the fields on soft ground at low speeds. This work focuses on the combined acoustic and mechanical development of a new exhaust system for an existing agricultural tractor, with the aim of providing a product with improved acoustic performances and a neater design. The host vehicle is equipped with a 300 hp diesel engine which can be particularly noisy at low rpm, with a further constraint being the “under the bonnet” available volume to fit the system into. The existing exhaust system is the baseline for the engineering process. The acoustic design is carried out by a 1D simulation software based on an electro-acoustic analogy, while the design modelling is performed by using Solidworks® 3D CAD. After the design stage a prototype has been manufactured and tested at the MWL/KTH laboratory. The engineering process gave the product a cleaner design and allowed to identify feasible solutions ensuring increased sound attenuation performances

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed

    Quantitative in situ hybridization for the evaluation of gene expression in asynchronous and synchronized cell cultures and in tissue sections

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    We describe an image analysis (IA) system that has been applied for the quantitative evaluation of mRNAs evidenced by in situ hybridization (ISH) with radiolabelled probes in cultured cells and in tissue sections. The ISH-IA method was used for the evaluation of cultured cell morphological parameters such as cell and nucleous area (CA and NA, respectively) in parallel with the levels of mRNAs detected as hybridization grains areas (GA). The evaluation of these parameters, together with the analysis of the levels of mRNAs (c-jun, cyclin A) specific for given cell cycle phases (i.e. G1 and S/G2), allowed the identification, in asynchronous cultures of human skin fibroblasts, of cells in G1 and S/G2 phases. The mRNA levels measured by ISH-AI were comparable with those detected by RT-PCR. This method was also applied for the analysis of fibronectin (FN) gene expression in control skin fibroblasts in relationship with the different phases of the cell cycle and in comparison with a tumor cell line (Sk-Hep1), heterogeneous either for morphometric parameters or for the levels of this transcript. Finally, the ISH-AI was applied for the semiquantitative evaluation of the expression, localization and alternative splicing pattern of FN mRNA in normal liver and in hepatocellular carcinoma (HCC) tissue sections

    Variations on the Author

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    “Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship

    Appropriate Similarity Measures for Author Cocitation Analysis

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    We provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis

    Dental trauma and bicycle safety: a report in Italian children and adolescents

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    OBJECTIVES: This retrospective study aims to analyze the pattern of oro-facial trauma from bicycle accidents in Italian children and adolescents, focusing on the safety devices used. METHODS: The medical records of 1405 patients of the Dental Clinic of the University of Brescia, between the age of 0 to 18, who experienced a dento-facial trauma from the use of a bicycle, were analyzed. Data regarding age, gender, weight, height, dominant hand, type of bicycle, use of safety devices, location and type of dental trauma, teeth involved, bone fractures and soft tissue lesions were recorded. Statistical analysis was performed. RESULTS: The majority of the traumatic events occurred in children within the 8-10 years of age-range; 1085 teeth were injured, of which 975 permanent teeth (89.9%) and 110 primary teeth (10.1%). The most common dental lesions were the coronal fractures (complicated and not complicated) while the most frequently involved teeth were the upper central incisors; 11% of patients were also treated for maxillo-facial fractures. A protective helmet was worn only in 3% of the cases; not one patient wore a mouth-guard. The use of helmets was more frequent in children and adolescents riding racing-bikes competitively, compared to those who were mountain bikers (p < 0.05). CONCLUSIONS: Bicycle accidents can have serious oro-facial consequences. Therefore, national and regional efforts should be made in Italy to promote head and mouth protection in cycling
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