• Title/Summary/Keyword: Maja

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The nose-up effect in twin-box bridge deck flutter: Experimental observations and theoretical model

  • Ronne, Maja;Larsen, Allan;Walther, Jens H.
    • Wind and Structures
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    • v.32 no.4
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    • pp.293-308
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    • 2021
  • For the past three decades a significant amount of research has been conducted on bridge flutter. Wind tunnel tests for a 2000 m class twin-box suspension bridge have revealed that a twin-box deck carrying 4 m tall 50% open area ratio wind screens at the deck edges achieved higher critical wind speeds for onset of flutter than a similar deck without wind screens. A result at odds with the well-known behavior for the mono-box deck. The wind tunnel tests also revealed that the critical flutter wind speed increased if the bridge deck assumed a nose-up twist relative to horizontal when exposed to high wind speeds - a phenomenon termed the "nose-up" effect. Static wind tunnel tests of this twin-box cross section revealed a positive moment coefficient at 0° angle of attack as well as a positive moment slope, ensuring that the elastically supported deck would always meet the mean wind flow at ever increasing mean angles of attack for increasing wind speeds. The aerodynamic action of the wind screens on the twin-box bridge girder is believed to create the observed nose-up aerodynamic moment at 0° angle of attack. The present paper reviews the findings of the wind tunnel tests with a view to gain physical insight into the "nose-up" effect and to establish a theoretical model based on numerical simulations allowing flutter predictions for the twin-box bridge girder.

The Role of Combined Multichannel Intraluminal Impedance-pH Monitoring in Infants with Brief, Resolved, Unexplained Events

  • Pavic, Ivan;Navratil, Marta;Bosanac, Maja;Fures, Jadranka Sekelj;Jurekovic, Irena Ivkovic;Hojsak, Iva
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.24 no.3
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    • pp.256-264
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    • 2021
  • Purpose: Data on the relationship between gastroesophageal reflux (GER) and brief resolved unexplained events (BRUE) in infants is scarce. The aim of this study was to identify the characteristics of combined multichannel intraluminal impedance-pH (MII-pH) monitoring in infants who have experienced BRUE. Methods: We conducted a prospective study of infants who were hospitalized on account of BRUE and required 24-hour MII-pH monitoring. Results: Twenty-one infants (mean age, 4.7 months; range, 0.9-8.9 months; male/female, 11/10) participated in this study. BRUE symptoms associated with GER were found in 10 infants (47.6%). Based on the RI on pH-metry alone, only 7 (33.3%) infants were diagnosed with GERD. More than 100 GER episodes detected by MII were found in 10 (47.6%) infants. Nineteen percent of infants were diagnosed with GERD based on both pH and MII. Conclusion: Both acid and non-acid reflux seem to play a significant role in the pathogenesis of GER-related BRUE in infants.

Increasing Frequency of Soft Tissue Sarcomas in Vojvodina - Comparison with the Literature

  • Dugandzija, Tihomir;Mikov, Marica Miladinov;Solajic, Nenad;Nikolin, Borislava;Trifunovic, Jasna;Ilic, Maja
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.2
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    • pp.1011-1014
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    • 2014
  • Background: Soft tissue sarcomas (STS) represent 1% of all malignant lesions. In this study the authors analyzed the incidence of STS in Vojvodina (the north region of Serbia) in the period from 1985 to 2009. A number of studies conducted worldwide indicate that STS incidence rates are tending to increase. Materials and Methods: On the basis of data from the Cancer Registry of Vojvodina, age standardized STS incidence rates were established as well as their linear trend, with data on histological structure, age, gender and STS distribution at specific locations. Results: The total number of registered patients was 1,308. Average age standardized rate was 1.90/100,000 per year. The investigated period showed a slight increase in the incidence rate (average annual percent increase=0.77%). The most frequent histological type was sarcoma not otherwise specified-NOS (27%), followed by leiomyosarcoma (21%), liposarcoma (14%), rhabdomyosarcoma (11%) and malignant fibrous histiocytoma (9%). The male/female ratio was 0.73:1. Every fifth patient was younger than 39. Conclusions: Comparison among eight international STS epidemiology studies show that the incidence rate range is between 1.4/100,000-5.0/100,000, though our finding is closer to the lower limit. Furthermore, the incidence rate increase was lower than that characteristic for the half of the analyzed studies. A partial explanation for that should be looked for among changes in diagnostic criteria and STS classifications.

Relationships between Genetic Diversity and Fusarium Toxin Profiles of Winter Wheat Cultivars

  • Goral, Tomasz;Stuper-Szablewska, Kinga;Busko, Maciej;Boczkowska, Maja;Walentyn-Goral, Dorota;Wisniewska, Halina;Perkowski, Juliusz
    • The Plant Pathology Journal
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    • v.31 no.3
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    • pp.226-244
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    • 2015
  • Fusarium head blight is one of the most important and most common diseases of winter wheat. In order to better understanding this disease and to assess the correlations between different factors, 30 cultivars of this cereal were evaluated in a two-year period. Fusarium head blight resistance was evaluated and the concentration of trichothecene mycotoxins was analysed. Grain samples originated from plants inoculated with Fusarium culmorum and naturally infected with Fusarium species. The genetic distance between the tested cultivars was determined and data were analysed using multivariate data analysis methods. Genetic dissimilarity of wheat cultivars ranged between 0.06 and 0.78. They were grouped into three distinct groups after cluster analysis of genetic distance. Wheat cultivars differed in resistance to spike and kernel infection and in resistance to spread of Fusarium within a spike (type II). Only B trichothecenes (deoxynivalenol, 3-acetyldeoxynivalenol and nivalenol) produced by F. culmorum in grain samples from inoculated plots were present. In control samples trichothecenes of groups A (H-2 toxin, T-2 toxin, T-2 tetraol, T-2 triol, scirpentriol, diacetoxyscirpenol) and B were detected. On the basis of Fusarium head blight assessment and analysis of trichothecene concentration in the grain relationships between morphological characters, Fusarium head blight resistance and mycotoxins in grain of wheat cultivars were examined. The results were used to create of matrices of distance between cultivars - for trichothecene concentration in inoculated and naturally infected grain as well as for FHB resistance Correlations between genetic distance versus resistance/mycotoxin profiles were calculated using the Mantel test. A highly significant correlation between genetic distance and mycotoxin distance was found for the samples inoculated with Fusarium culmorum. Significant but weak relationships were found between genetic distance matrix and FHB resistance or trichothecene concentration in naturally infected grain matrices.