1,721,001 research outputs found
Road pollution analysis dynamic model (ropadym)
No full textThe pollutant diffusion adjacent to the motorway is strongly influenced by the vehicle induced turbulence. In spring 2001, turbulence measures were carried out in order to evaluate the phenomena intensity and range on the motorway from Mannheim to Heidelberg. It was found that the vehicle induced turbulence has more energy than the natural atmospheric turbulence until a distance of 40-50 meters from the motorway under particular meteorological conditions. Many attempts to create models and mathematical formulas for pollutant concentration distribution evaluations are found in the relevant technical literature. These limit the analysis to two dimensional urban U-sections without taking into account the vehicular transmitted energy to the air. The Road Pollution Analysis using the three dimensional Dynamic Models (ROPADYM). implemented with computational fluid dynamics (CFD) codes which take into account the vehicular motion and consequently the vehicular traffic induced Turbulent Kinetic Energy (TKE). With this approach more accurate pollutant distributions evaluations and predictions in the proximity of road infrastructures is done. This infrastructure can be urban or suburban, a U-section, a tunnel or a discontinuity (e.g. tunnel fornix). ROPADYM models are implemented with the “sliding mesh” technique that allows a faster calculation with a high level definition compared to adaptive mesh techniques. Case studies are worked out and a comparison is given with two dimensional classical approaches
Misura e mitigazione dell’impatto ambientale da traffico veicolare in galleria
No full textThe volumes of a road tunnel including the tunnel exits, affected by the plume effect were analysed by an original numerical simulation model named RO.P.A.DY.M. (ROad Pollution Analysis DYnamic Model). This model was developed by taking into account the fluid-dynamic effects of road-vehicle motion in order to carry out the map of atmospheric pollutant concentrations within the foregoing volumes in near-to-real conditions. With the use of an innovative CFM method (Control Function Method) an objective measure of the environmental impact of road traffic for the foregoing volumes was obtained. The introduction of air-cleaning active systems in the tunnel and at the exits was considered. With the application of the ROPADYM model pollutant concentration maps were produced for the volumes considered in the tunnel, taking into account the cleansing systems. In conclusion, a quantitative evaluation of the effects obtained from the application of these active systems was formulated. This evaluation is expressed for the reduction in both pollutant concentrations and environmental impact
Hypertransaminasemia in childhood as a marker of genetic liver disorders.
No full textBACKGROUND: The widespread use of routine biochemical assays has led to increased incidental findings of hypertransaminasemia. We aimed to evaluate the prevalence of different causes of raised aminotransferase levels in children referred to a university department of pediatrics.
METHODS: We investigated 425 consecutive children (age range, 1-18 years) with isolated hypertransaminasemia. All patients had raised aminotransferase levels on at least two occasions in the last month before observation. Cases due to major hepatotropic viruses were excluded.
RESULTS: During the first 6 months of observation, 259 children showed normalized liver enzymes. Among the remaining 166 patients with hypertransaminasemia lasting for more than 6 months, 75 had obesity-related liver disease; 51, genetic disorders; 7, autoimmune hepatitis; 5, cholelithiasis; 3, choledochal cyst; and 3, celiac disease. Among the 51 children with genetic disorders, 18 had Wilson disease; 14, muscular dystrophy; 4, alpha-1-antitrypsin deficiency; 4, Alagille syndrome; 4, hereditary fructose intolerance; 3, glycogen storage disease (glycogenosis IX); 2, ornithine transcarbamylase deficiency; and 2, Shwachman's syndrome. In 22 children, the hypertransaminasemia persisted for more than 6 months in the absence of a known cause.
CONCLUSIONS: Genetic disease accounted for 12% of cases of isolated hypertransaminasemia observed in a tertiary pediatric department. A high level of suspicion is desirable for an early diagnosis of these disorders, which may present with isolated hypertransaminasemia and absence of typical clinical signs
Long-term outcome of children with chronic hepatitis B: a 24-year observation period.
No full textChronic hepatitis B seems to manifest as mild disease in children and young adults. However, data regarding the long-term course of hepatitis B in untreated and interferon-treated children are still scarce. This study investigates the long-term outcome of disease in a large series of untreated and treated children with hepatitis B virus (HBV) infection. METHODS: Clinical, biochemical, virological, and histological features were evaluated in children (age range, 2-18 years) with chronic HBV infection who did not have concomitant chronic systemic diseases other than HBV infection and who were admitted to the liver unit in the Department of Pediatrics at University "Frederico II" (Naples, Italy) during the period 1981-2005. RESULTS: One hundred eight consecutive patients observed for up to 24 years were studied. During the observation period, 67 children remained untreated, and 41 were treated with interferon-alpha. After a median period of observation of 12.1 years (range, 5-23 years), hepatitis B early antigen loss and serum HBV DNA clearance occurred in 43 untreated patients (69.3%) who were hepatitis B early antigen positive at study entry and in 33 treated children (80%; the P value is not statistically significant). In addition, 6 untreated patients (9.7%) and 4 treated patients (9.7%) became anti-HBs [corrected] positive at the end of the follow-up period. Histological assessment, evaluated for 57 children, showed mild-to-moderate disease in 91.2% of cases of HBV infection. No patient developed end-stage liver disease or hepatocellular carcinoma. CONCLUSIONS: Children with chronic HBV infection are symptom free, with morphologically mild liver disease. Considering that the overall long-term outcomes did not differ between treated and untreated patients, the real impact of therapy on the long-term course of HBV infection remains to be established. Additional studies are needed to confirm our conclusions
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Variations on the Author
Get PDF“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
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